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CPrimerPlus第版编程练习答案已

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Chapter 2 Programming ExercisesPE 2--‐1/* Programming Exercise 2-1 */#include <stdio.h>int main(void){ printf("GustavMahler\n");printf("Gustav\nMahler\n");printf("Gustav ");printf("Mahler\n");return 0;}PE 2--‐3#include <stdio.h>int main(void){ inttoes;toes = 10;printf("toes = %d\n", toes);printf("Twice toes = %d\n", 2 * toes);printf("toes squared = %d\n", toes * toes);return 0;}/* or create two more variables, set them to 2 * toes and toes * toes */PE 2--‐8/* Programming Exercise 2-8 */#include <stdio.h>voidone_three(void);void two(void);int main(void){printf("startingnow:\n"); one_three();printf("done!\n");return 0;}void one_three(void){printf("one\n");two();printf("three\n");/* Programming Exercise 3-6 */#include <stdio.h>int main(void){float mass_mol = 3.0e-23; /* mass of water molecule in grams*/ float mass_qt = 950; /* mass of quart of water ingrams */ float quarts; float molecules;printf("Enter the number of quarts of water: ");scanf("%f", &quarts);molecules = quarts * mass_qt / mass_mol;printf("%f quarts of water contain %e molecules.\n", quarts, molecules); return 0;}Chapter 4 Programming ExercisesPE 4--‐1/* Programming Exercise 4-1 */#include <stdio.h>int main(void){ charfname[40];char lname[40];printf("Enter your first name:"); scanf("%s", fname);printf("Enter your last name: ");scanf("%s", lname);printf("%s, %s\n", lname, fname);return 0;}#include <stdio.h>int main(void){ const int minperhour= 60; int minutes,hours, mins;printf("Enter the number of minutes to convert:"); scanf("%d", &minutes); while (minutes >0 ){ hours = minutes /minperhour; mins =minutes % minperhour;printf("%d minutes = %d hours, %d minutes\n", minutes, hours, mins); printf("Enter next minutes value (0 to quit): "); scanf("%d", &minutes);}printf("Bye\n");return 0;}PE 5--‐3/* Programming Exercise 5-3 */#include <stdio.h>int main(void){ const int daysperweek= 7; int days, weeks,day_rem;printf("Enter the number of days:"); scanf("%d", &days); while(days > 0){ weeks = days /showCube(val); return 0; }void showCube(double x){printf("The cube of %e is %e.\n", x, x*x*x );}Chapter 6 Programming ExercisesPE 6--‐1/* pe6-1.c *//* this implementation assumes the character codes */ /* are sequential, as they are in ASCII. */ #include <stdio.h> #defineSIZE 26 int main( void ){ char lcase[SIZE];int i; for (i = 0;i < SIZE; i++)lcase[i] = 'a' + i; for(i = 0; i < SIZE; i++)printf("%c", lcase[i]);printf("\n");return 0;}PE 6--‐3/* pe6-3.c *//* this implementation assumes the character codes *//* are sequential, as they are in ASCII. */#include <stdio.h>int main( void ){ char let ='F'; charint main( void ){ doublen, m;double res;printf("Enter a pair of numbers: ");while (scanf("%lf %lf", &n, &m) == 2){res = (n - m) / (n * m);printf("(%.3g - %.3g)/(%.3g*%.3g) = %.5g\n", n, m, n, m, res); printf("Enter next pair (non-numeric to quit): ");}return 0;}PE 6--‐11/* pe6-11.c */#include<stdio.h>#define SIZE 8intmain( void ){ intvals[SIZE];int i;printf("Please enter %d integers.\n",SIZE); for (i = 0; i < SIZE; i++)scanf("%d", &vals[i]);printf("Here, in reverse order, are the values you entered:\n"); for (i = SIZE - 1; i >= 0; i--)printf("%d ", vals[i]); printf("\n"); return 0;}{ double arr[SIZE];double arr_cumul[SIZE];int i;printf("Enter %d numbers:\n",SIZE);for (i = 0; i < SIZE; i++){printf("value #%d: ", i +1); scanf("%lf", &arr[i]);/* or scanf("%lf", arr + i); */}arr_cumul[0] = arr[0]; /* set first element */for (i = 1; i < SIZE; i++)arr_cumul[i] = arr_cumul[i-1] + arr[i];for (i = 0; i < SIZE; i++)printf("%8g ", arr[i]);printf("\n"); for (i = 0; i <SIZE; i++) printf("%8g ",arr_cumul[i]); printf("\n"); return 0;}PE 6--‐16/* pe6-16.c */#include <stdio.h>#define RATE_SIMP 0.10#define RATE_COMP 0.05#define INIT_AMT 100.0int main( void ){return 0;}PE 7--‐3/* Programming Exercise 7-3 */#include <stdio.h>int main(void){ int n;double sumeven = 0.0;int ct_even = 0;double sumodd = 0.0;int ct_odd = 0;while (scanf("%d", &n) == 1 && n != 0){if (n % 2 == 0){sumeven += n;++ct_even;}else // n % 2 is either 1 or -1{sumodd += n;++ct_odd;} }printf("Number of evens: %d", ct_even); if (ct_even > 0)printf(" average: %g", sumeven /ct_even); putchar('\n');printf("Number of odds: %d", ct_odd);return 0;}PE 7--‐7// Programming Exercise 7-7#include <stdio.h>#define BASEPAY 10 // $10 per hour#define BASEHRS 40 // hours at basepay #define OVERTIME 1.5 // 1.5 time#define AMT1 300 // 1st rate tier#define AMT2 150 // 2st rate tier#define RATE1 0.15 // rate for 1st tier #define RATE2 0.20 // rate for 2nd tier #define RATE3 0.25 // rate for 3rd tier int main(void){double hours;double gross;double net;double taxes;printf("Enter the number of hours worked this week:"); scanf("%lf", &hours); if (hours <= BASEHRS)gross = hours * BASEPAY; elsegross = BASEHRS * BASEPAY + (hours - BASEHRS) * BASEPAY *OVERTIME; if (gross <= AMT1) taxes = gross * RATE1;else if (gross <= AMT1 + AMT2)taxes = AMT1 * RATE1 + (gross - AMT1) * RATE2;elsetaxes = AMT1 * RATE1 + AMT2 * RATE2 + (gross - AMT1 - AMT2) * RATE3; net = gross - taxes;printf("gross: $%.2f; taxes: $%.2f; net: $%.2f\n", gross, taxes, net);PE 7--‐11/* pe7-11.c *//* Programming Exercise 7-11 */#include <stdio.h>#include <ctype.h>int main(void){const double price_artichokes =2.05; const double price_beets =1.15; const double price_carrots= 1.09; const doubleDISCOUNT_RATE = 0.05; constdouble under5 = 6.50; constdouble under20 = 14.00; constdouble base20 = 14.00; constdouble extralb = 0.50;charch;double lb_artichokes =0; double lb_beets =0; double lb_carrots= 0; double lb_temp;double lb_total;doublecost_artichokes;double cost_beets;double cost_carrots;double cost_total;double final_total;shipping = base20 + extralb * lb_total;if (cost_total > 100.0)discount = DISCOUNT_RATE *cost_total; else discount = 0.0;final_total = cost_total + shipping - discount;printf("Your order:\n");printf("%.2f lbs of artichokes at $%.2f perpound:$ %.2f\n", lb_artichokes,price_artichokes, cost_artichokes); printf("%.2f lbs of beets at $%.2f per pound: $%.2f\n",lb_beets, price_beets, cost_beets); printf("%.2f lbs of carrots at $%.2f per pound: $%.2f\n",lb_carrots, price_carrots, cost_carrots); printf("Total cost of vegetables: $%.2f\n", cost_total); if(cost_total > 100)printf("Volume discount: $%.2f\n",discount); printf("Shipping: $%.2f\n",shipping); printf("Total charges: $%.2f\n",final_total); return 0; }Chapter 8 Programming ExercisesPE 8--‐1/* Programming Exercise 8-1 */#include <stdio.h>int main(void) { int ch;int ct = 0; while ((ch= getchar()) != EOF)ct++;printf("%d characters read\n", ct);#include <stdio.h> #include<ctype.h> int main(void){ int high = 100; intlow = 1; int guess =(high + low) / 2; charresponse;printf("Pick an integer from 1 to 100. I will try to guess "); printf("it.\nRespond with a y if my guess is right, with");printf("\na h if it is high, and with an l if it is low.\n"); printf("Uh...is your number %d?\n", guess);while ((response = getchar()) != 'y') /* get response */{if (response == '\n')continue;if (response != 'h' && response != 'l'){printf("I don't understand that response. Please enter hfor\n"); printf("high, l for low, or y for correct.\n");continue;}if (response == 'h')high = guess - 1;else if (response == 'l')low = guess + 1;guess = (high + low) / 2;printf("Well, then, is it %d?\n", guess);}printf("I knew I could do it!\n");return 0;}case 'a': pay = BASEPAY1; break;case 'b': pay = BASEPAY2; break;case 'c': pay = BASEPAY3; break;case 'd': pay = BASEPAY4; break;default : printf("Please enter a, b, c, d, or q.\n"); menu();continue; // go to beginning of loop}printf("Enter the number of hours worked this week:"); scanf("%lf", &hours); if (hours <=BASEHRS) gross = hours * pay; elsegross = BASEHRS * pay + (hours - BASEHRS) * pay *OVERTIME; if (gross <= AMT1) taxes = gross *RATE1; else if (gross <= AMT1 + AMT2)taxes = AMT1 * RATE1 + (gross - AMT1) * RATE2;elsetaxes = AMT1 * RATE1 + AMT2 * RATE2 + (gross - AMT1 - AMT2) * RATE3; net = gross - taxes;printf("gross: $%.2f; taxes: $%.2f; net: $%.2f\n", gross,taxes, net); menu(); }printf("Done.\n");return 0;}void menu(void){printf("********************************************************""*********\n");printf("Enter the letter corresponding to the desired pay rate"" or action:\n");}double min(double a, double b){return a < b ? a : b;}/* alternative implementationdouble min(double a, double b){ if (a <b)return a;elsereturn b;}*/PE 9--‐3/* Programming Exercise 9-3 */#include <stdio.h>void chLineRow(char ch, int c, int r);int main(void){ char ch; int col, row;printf("Enter a character (# to quit): ");while ( (ch = getchar()) != '#'){ if (ch== '\n')continue;printf("Enter number of columns and number of rows: "); if (scanf("%d %d", &col, &row) != 2) break; chLineRow(ch, col, row);printf("\nEnter next character (# to quit): ");void larger_of(double *p1, double *p2){ if (*p1 >*p2)*p2 = *p1;else*p1 = *p2;}// alternatively:/*void larger_of(double *p1, double *p2){*p1= *p2 = *p1 > *p2 ? *p1 : *p2;}*/PE 9--‐8/* Programming Exercise 9-8 */#include <stdio.h>double power(double a, int b); /* ANSI prototype */int main(void) { double x, xpow; int n;printf("Enter a number and the integer power");printf(" to which\nthe number will be raised. Enterq"); printf(" to quit.\n"); while (scanf("%lf%d",&x, &n) == 2){ xpow = power(x,n); /* function call */ printf("%.3g to the power %d is %.5g\n", x, n, xpow); printf("Enter next pair of numbers or q toputchar('\n');printf("Enter an integer (q to quit):\n");}printf("Done.\n");return 0;}void to_base_n(int x, int base) /* recursive function */ { int r; r = x % base;if (x >= base)to_base_n(x / base, base);putchar('0' + r); return;}Chapter 10 Programming ExercisesPE 10--‐1/* Programming Exercise 10-1 */#include <stdio.h>#define MONTHS 12 // number of months in ayear #define YRS 5 // number of years ofdata int main(void){// initializing rainfall data for 2010 - 2014const float rain[YRS][MONTHS] = {{4.3,4.3,4.3,3.0,2.0,1.2,0.2,0.2,0.4,2.4,3.5,6.6},{8.5,8.2,1.2,1.6,2.4,0.0,5.2,0.9,0.3,0.9,1.4,7.3},{9.1,8.5,6.7,4.3,2.1,0.8,0.2,0.2,1.1,2.3,6.1,8.4},{7.2,9.9,8.4,3.3,1.2,0.8,0.4,0.0,0.6,1.7,4.3,6.2},{7.6,5.6,3.8,2.8,3.8,0.2,0.0,0.0,0.0,1.3,2.6,5.2}int orig[LEN] = {1,2,3,4,12,6,7,8,9,10};int max;show_arr(orig, LEN); max =max_arr(orig, LEN); printf("%d =largest value\n", max);return 0;}int max_arr(const int ar[], int n){ int i;int max = ar[0];/* don't use 0 as initial max value -- fails if all array values are neg */ for (i = 1; i < n;i++) if (max <ar[i]) max =ar[i]; return max;}void show_arr(const int ar[], int n){ int i; for(i = 0; i < n; i++)printf("%d ", ar[i]);putchar('\n');}PE 10--‐5/* Programming Exercise 10-5 */#include <stdio.h>#define LEN 10double max_diff(const double ar[], int n);void show_arr(const double ar[], int n);#define LEN1 7#define LEN23void copy_arr(int ar1[], const int ar2[], int n); void show_arr(const int [], int);intmain(void){int orig[LEN1] ={1,2,3,4,5,6,7}; intcopy[LEN2];show_arr(orig, LEN1);copy_arr(copy, orig + 2, LEN2);show_arr(copy, LEN2);return 0;}void copy_arr(int ar1[], const int ar2[], int n){ int i;for (i = 0; i < n; i++)ar1[i] = ar2[i];}void show_arr(const int ar[], int n){ int i; for(i = 0; i < n; i++)printf("%d ", ar[i]);putchar('\n');}PE 10--‐11/* Programming Exercise 10-11 */#include <stdio.h>#include <stdio.h>#define ROWS 3#define COLS 5void store(double ar[], int n);double average2d(int rows, int cols, doublear[rows][cols]); double max2d(int rows, int cols, doublear[rows][cols]); void showarr2(int rows, int cols, doublear[rows][cols]); double average(const double ar[], int n); int main(void){ doublestuff[ROWS][COLS];int row;for (row = 0; row < ROWS; row++){printf("Enter %d numbers for row %d\n", COLS, row + 1);store(stuff[row], COLS);} printf("arraycontents:\n");showarr2(ROWS, COLS, stuff);for (row = 0; row < ROWS; row++)printf("average value of row %d = %g\n", row + 1, average(stuff[row], COLS)); printf("average value of all rows = %g\n", average2d(ROWS, COLS, stuff)); printf("largest value = %g\n", max2d(ROWS, COLS, stuff)); printf("Bye!\n"); return 0;} void store(double ar[],int n){ int i;for (i = 0; i < n; i++){}double average(const double ar[], int n){ int i;double sum = 0.0;for (i = 0; i <n; i++) sum +=ar[i]; if (n > 0)return sum / n;else return 0.0;}Chapter 11 Programming ExercisesPE 11--‐1/* Programming Exercise 11-1 */#include <stdio.h> #define LEN 10char * getnchar(char * str, intn); int main(void) { charinput[LEN]; char *check; check = getnchar(input, LEN - 1);if (check == NULL)puts("Input failed."); else puts(input); puts("Done.\n"); return 0;}char * getnchar(char * str, int n){ int i;int ch;for (i = 0; i < n;i++) { ch === EOF) returnNULL; else{ while (ch !='\n') ch =getchar();return orig;}}PE 11--‐6/* Programming Exercise 11-6 */#include <stdio.h>#include <string.h>#define LEN 80_Bool is_within(const char * str, char c);char * s_gets(char * st, int n);int main(void){ charinput[LEN];char ch; intfound;;printf("Enter a string: ");while (s_gets(input, LEN) && input[0] != '\0') {printf("Enter a character:"); ch = getchar();while (getchar() != '\n')continue; found =is_within(input, ch); if(found == 0)int main(void){char orig[LEN] ="transportation"; char * find;puts(orig);find = string_in(orig,"port"); if (find)puts(find); elseputs("Not found"); find =string_in(orig, "part"); if(find) puts(find);elseputs("Not found");return 0;}#include <string.h>char * string_in(const char * s1, const char * s2){int l2 = strlen(s2);int tries; /* maximum number of comparisons */ int nomatch = 1; /* set to 0 if match is found */tries = strlen(s1) + 1 - l2;if (tries > 0)while (( nomatch = strncmp(s1, s2, l2)) &&tries--) s1++; if (nomatch)return NULL; elsereturn (char *) s1; /* cast const away */}PE 11--‐10(*pos);}elses++;}}char * s_gets(char * st, int n){ char *ret_val;char * find;ret_val = fgets(st, n,stdin); if (ret_val) {find = strchr(st, '\n'); // look for newlineif (find) // if the address is not NULL,*find = '\0'; // place a null character thereelsewhile (getchar() != '\n')continue;}return ret_val;}PE 11--‐12/* pe11-12.c -- counts words and certain characters *//* Programming Exercise 11-11 */#include <stdio.h>#include <ctype.h> // for isspace()#include <stdbool.h> // for bool, true, falseint main(void){#include <math.h> /* for pow() */int main(int argc, char*argv[]){double num, exp;if(argc != 3)printf("Usage: %s number exponent\n",argv[0]); else { num =atof(argv[1]); exp = atof(argv[2]);printf("%f to the %f power = %g\n", num, exp, pow(num,exp)); }return 0;}PE 11--‐16/* Programming Exercise 11-16 */#include <stdio.h>#include <ctype.h>int main(int argc, char*argv[]){ char mode ='p'; int ok= 1; int ch;if (argc > 2){printf("Usage: %s [-p | -u | -l]\n", argv[0]); ok = 0; /* skip processing input */}else if (argc == 2)/* Programming Exercise 12-1 *//* one of several approaches */#include <stdio.h>void critic(int *u); int main(void){int units; /* units now local */printf("How many pounds to a firkin ofbutter?\n"); scanf("%d", &units); while( units != 56) critic(&units);printf("You must have looked it up!\n");return 0;}void critic(int * u){printf("No luck, my friend. Try again.\n");scanf("%d", u);}// or use a return value:// units = critic();// and have critic look like this:/* intcritic(void){ int u;printf("No luck, my friend. Tryagain.\n"); scanf("%d", &u); returnu;}*/// or have main() collect the next value for unitsvoid show_info(int mode, double distance, double fuel){printf("Fuel consumption is ");if (mode == METRIC)printf("%.2f liters per 100 km.\n", 100 * fuel / distance); elseprintf("%.1f miles per gallon.\n", distance / fuel);}// pe12-3b.c// compile with pe12-3a.c#include <stdio.h>#include "pe12-3a.h"int main(void){ int mode; intprev_mode = METRIC;double distance, fuel;printf("Enter 0 for metric mode, 1 for US mode:"); scanf("%d", &mode); while (mode >= 0){ check_mode(&mode); if (mode ==USE_RECENT) mode = prev_mode;prev_mode = mode; get_info(mode, &distance,&fuel); show_info(mode, distance, fuel);printf("Enter 0 for metric mode, 1 for US mode"); printf(" (-1 to quit): "); scanf("%d", &mode);}printf("Done.\n");return0;/* print.c -- prints an array */ voidprint(const int array[], int limit){int index;for (index = 0; index < limit; index++){printf("%2d ", array[index]);if (index % 10 == 9)putchar('\n');}if (index % 10 != 0) // if last line not complete putchar('\n');}PE 12--‐7/* pe12-7.c */#include <stdio.h>#include <stdlib.h> /* for srand() */#include <time.h> /* for time() */int rollem(int);int main(void){int dice, count,roll; int sides;int set, sets;srand((unsigned int) time(0)); /* randomize rand() */printf("Enter the number of sets; enter q to stop: ");while (scanf("%d", &sets) == 1){FILE * target;if (argc != 3){printf("Usage: %s sourcefile targetfile\n", argv[0]);exit(EXIT_FAILURE);} if ((source = fopen(argv[1],"rb")) == NULL){printf("Could not open file %s for input\n", argv[1]); exit(EXIT_FAILURE);}if ((target = fopen(argv[2], "wb")) == NULL){printf("Could not open file %s for output\n", argv[2]); exit(EXIT_FAILURE);}while ((byte = getc(source)) != EOF){putc(byte, target);}if (fclose(source) != 0)printf("Could not close file %s\n", argv[1]);if (fclose(target) != 0)printf("Could not close file %s\n", argv[2]);return 0;}#include <stdlib.h>#include <string.h>#define BUFSIZE 4096#define SLEN 81void append(FILE *source, FILE *dest);int main(int argc, char *argv[]){FILE *fa, *fs;int files = 0;int fct;if (argc < 3){ printf("Usage: %s appendfile sourcefile[s]\n",argv[0]); exit(EXIT_FAILURE);} if ((fa = fopen(argv[1], "a"))== NULL){fprintf(stderr, "Can't open %s\n", argv[1]);exit(EXIT_FAILURE);}if (setvbuf(fa, NULL, _IOFBF, BUFSIZE) != 0){ fputs("Can't create output buffer\n",stderr); exit(EXIT_FAILURE);}for (fct = 2; fct < argc; fct++){if (strcmp(argv[fct], argv[1]) == 0)fputs("Can't append file to itself\n",stderr);else if ((fs = fopen(argv[fct], "r")) == NULL)fprintf(stderr, "Can't open %s\n", argv[fct]);else {FILE * f2;if (argc != 3){printf("Usage: %s file1 file2\n", argv[0]);exit(EXIT_FAILURE);}if ((f1 = fopen(argv[1], "r")) == NULL){ printf("Could not open file %s for input\n",argv[1]); exit(EXIT_FAILURE);}if ((f2 = fopen(argv[2], "r")) == NULL){printf("Could not open file %s for input\n", argv[2]); exit(EXIT_FAILURE);} ch1 =getc(f1);ch2 = getc(f2);while (ch1 != EOF || ch2 != EOF){while (ch1 != EOF && ch1 != '\n') /* skipped after EOF reached*/{ putchar(ch1); ch1 =getc(f1);}if (ch1 != EOF){putchar('\n');ch1 = getc(f1);printf("Usage: %s file1 file2\n", argv[0]);exit(EXIT_FAILURE);}if ((f1 = fopen(argv[1], "r")) == NULL){ printf("Could not open file %s for input\n",argv[1]); exit(EXIT_FAILURE);}if ((f2 = fopen(argv[2], "r")) == NULL){printf("Could not open file %s for input\n", argv[2]); exit(EXIT_FAILURE);} ch1 =getc(f1);ch2 = getc(f2);while (ch1 != EOF || ch2 != EOF){while (ch1 != EOF && ch1 != '\n') /* skipped after EOF reached */{ putchar(ch1); ch1 =getc(f1);}if (ch1 != EOF){if (ch2 == EOF)putchar('\n');elseputchar(' ');ch1 = getc(f1);}fprintf(stderr,"Can't open \"words\" file.\n");exit(EXIT_FAILURE);}// determine current number of linesrewind(fp);while (fgets(words, MAX, fp) != NULL) wordct++; rewind(fp); puts("Enter words to add to the file;press the #"); puts("key at the beginning of a line to terminate."); while ((fscanf(stdin,"%40s", words) == 1) &&(words[0] != '#')) fprintf(fp, "%3d: %s\n", ++wordct, words); puts("File contents:");rewind(fp); // go back to beginning of file while (fgets(words, MAX, fp) != NULL) // read line including number fputs(words, stdout); if (fclose(fp) != 0)fprintf(stderr,"Error closing file\n");puts("Done");return 0;}PE 13--‐11/* Programming Exercise 13-11 */#include <stdio.h>#include <stdlib.h>#include <string.h>#define SLEN 256const char *errmesg[] = {"Usage: %s string filename]\n","Can't open file %s\n" };int main(int argc, char *argv[]){FILE *fp;895 5 5 5 5 5 5 5 5 5 5 5 5 8 9 9 8 5 5 5 5 5 5 5 5 5 5 5 5 5 0 0 0 0 0 0 0 0 0 0 0 0 5 8 9 9 8 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 8 9 9 8 5 0 0 0 06 6 0 0 0 0 0 0 0 0 0 0 2 2 0 0 0 0 0 0 5 8 9 9 8 5 0 0 5 6 0 0 6 5 0 0 0 0 0 0 0 0 3 3 0 0 0 0 0 0 5 8 9 9 8 5 0 5 6 1 1 1 1 6 5 0 0 0 0 0 0 0 4 4 0 0 0 0 0 0 5 8 9 9 8 5 0 0 5 6 0 0 6 5 0 0 0 0 0 0 0 0 5 5 0 0 0 0 0 0 5 8 9 9 8 5 0 0 0 0 6 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 8 9 9 8 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 8 9 9 8 5 0 0 0 0 0 0 0 0 0 0 0 0 PE 13--‐12/* Programming Exercise 13-12 */#include <stdio.h>#include <stdlib.h>#define ROWS 20#define COLS 30#define LEVELS 10const char trans[LEVELS + 1] = " .':~*=&%@";void MakePic(int data[][COLS], char pic[][COLS], int rows); void init(char arr[][COLS], char ch);int main() { int row,col; intpicIn[ROWS][COLS];char picOut[ROWS][COLS];char fileName[81];FILE *infile;init(picOut, 'S');printf("Enter name offile: "); scanf("%80s",fileName);if ((infile = fopen(fileName, "r")) == NULL)PE 14--‐1/* pe14-1.c */#include <stdio.h>#include <string.h>#include <ctype.h>struct month{ charname[10];char abbrev[4];int days;int monumb;}; const struct monthmonths[12] = { {"January","Jan", 31, 1},{"February", "Feb", 28, 2},{"March", "Mar", 31, 3},{"April", "Apr", 30, 4},{"May", "May", 31, 5},{"June", "Jun", 30, 6},{"July", "Jul", 31, 7},{"August", "Aug", 31, 8},{"September", "Sep", 30, 9},{"October", "Oct", 31, 10},{"November", "Nov", 30, 11},{"December", "Dec", 31, 12}}; intdays(char * m);int main(void){ charinput[20];#include <string.h>char * s_gets(char * st, int n);#define MAXTITL 40#define MAXAUTL 40#define MAXBKS 100 /* maximum number of books*/ struct book { /* set up book template */ char title[MAXTITL]; char author[MAXAUTL]; float value;};void sortt(struct book * pb[], int n);void sortv(struct book * pb[], int n);int main(void){ struct book library[MAXBKS]; /* array of bookstructures */ struct book * pbk[MAXBKS]; /* pointersfor sorting */ int count = 0; int index;。

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cprimer plus第版编程练习答案已

cprimer plus第版编程练习答案已

Chapter 2Programming ExercisesPE 2--‐1/*ProgrammingExercise2-1*/#include<stdio.h>intmain(void){printf("GustavMahler\n");printf("Gustav\nMahler\n");printf("Gustav");printf("Mahler\n");return0;}PE 2--‐3/*ProgrammingExercise2-3*/#include<stdio.h>intmain(void){intageyears;/*ageinyears*/intagedays;/*ageindays*//*largeagesmayrequirethelongtype*/ageyears=101;agedays=365*ag eyears;printf("Anageof%dyearsis%ddays.\n",ageyears,agedays);return0; }PE 2--‐4/*ProgrammingExercise2-4*/#include<stdio.h>voidjolly(void);voiddeny(void);intmain(void){jolly();jolly();jolly();deny();return0;}voidjolly(void){printf("Forhe'sajollygoodfellow!\n");}voiddeny(void){printf("Whichnobodycandeny!\n");}PE 2--‐6/*ProgrammingExercise2-6*/#include<stdio.h>intmain(void){inttoes;toes=10;printf("toes=%d\n",toes);printf("Twicetoes=%d\n",2*toes);printf("toessquared=%d\n",toes*toes);return0;}/*orcreatetwomorevariables,setthemto2*toesandtoes*toes*/ PE 2--‐8/*ProgrammingExercise2-8*/#include<stdio.h>voidone_three(void);voidtwo(void);intmain(void){printf("startingnow:\n");one_three();printf("done!\n");return0;}voidone_three(void){printf("one\n");two();printf("three\n");}voidtwo(void){printf("two\n");}Chapter 3Programming ExercisesPE 3--‐2/*ProgrammingExercise3-2*/#include<stdio.h>intmain(void){intascii;printf("EnteranASCIIcode:");scanf("%d",&ascii);printf("%distheASCIIcodefor%c.\n",ascii,ascii);return0; }PE 3--‐4/*ProgrammingExercise3-4*/#include<stdio.h>intmain(void){floatnum;printf("Enterafloating-pointvalue:");scanf("%f",&num); printf("fixed-pointnotation:%f\n",num);printf("exponentialnotation:%e\n",num);printf("pnotation:%a\n",num);return0;}PE 3--‐6/*ProgrammingExercise3-6*/#include<stdio.h>intmain(void){floatmass_mol=3.0e-23;/*massofwatermoleculeingrams*/floatmass_qt=950;/*massofquartofwat eringrams*/floatquarts;floatmolecules;printf("Enterthenumberofquartsofwater:");scanf("%f",&quarts);molecules=quarts*mass_qt/mass_mol;printf("%fquartsofwatercontain%emolecules.\n",quarts,molecules);return0; }Chapter 4Programming ExercisesPE 4--‐1/*ProgrammingExercise4-1*/#include<stdio.h>intmain(void){charfname[40];charlname[40];printf("Enteryourfirstname:");scanf("%s",fname);printf("Enteryourlastname:");scanf("%s",lname);printf("%s,%s\n",lname,fname);return0;}PE 4--‐4/*ProgrammingExercise4-4*/#include<stdio.h>intmain(void){floatheight;charname[40];printf("Enteryourheightininches:");scanf("%f",&height);printf("Enteryourname:");scanf("%s",name);printf("%s,youare%.3ffeettall\n",name,height/12.0);return0;}PE 4--‐7/*ProgrammingExercise4-7*/#include<stdio.h>#include<float.h>intmain(void){floatot_f=1.0/3.0;doubleot_d=1.0/3.0;printf("floatvalues:");printf("%.4f%.12f%.16f\n",ot_f,ot_f,ot_f);printf("doublevalues:");printf("%.4f%.12f%.16f\n",ot_d,ot_d,ot_d);printf("FLT_DIG:%d\n",FLT_DIG);printf("DBL_DIG:%d\n",DBL_DIG);return0;}Chapter 5Programming ExercisesPE 5--‐1/*ProgrammingExercise5-1*/#include<stdio.h>intmain(void){constintminperhour=60;intminutes,hours,mins;printf("Enterthenumberofminutestoconvert:");scanf("%d",&minutes);while(minutes>0){hours=minutes/minperhour;mins=minutes%minperhour;printf("%dminutes=%dhours,%dminutes\n",minutes,hours,mins);printf("Enterne xtminutesvalue(0toquit):");scanf("%d",&minutes);}printf("Bye\n");return0;}PE 5--‐3/*ProgrammingExercise5-3*/#include<stdio.h>intmain(void){constintdaysperweek=7;intdays,weeks,day_rem;printf("Enterthenumberofdays:");scanf("%d",&days);while(days>0){weeks=days/daysperweek;day_rem=days%daysperweek;printf("%ddaysare%dweeksand%ddays.\n",days,weeks,day_rem);printf("Enterthenumberofdays(0orlesstoend):");scanf("%d",&days);}printf("Done!\n");return0;}PE 5--‐5/*ProgrammingExercise5-5*/#include<stdio.h>intmain(void)/*findssumoffirstnintegers*/{intcount,sum;intn;printf("Entertheupperlimit:");scanf("%d",&n);count=0;sum=0;while(count++<n)sum=sum+count;printf("sum=%d\n",sum);return0;}PE 5--‐7/*ProgrammingExercise5-7*/#include<stdio.h>voidshowCube(doublex);intmain(void)/*findscubeofenterednumber*/ {doubleval;printf("Enterafloating-pointvalue:");scanf("%lf",&val);showCube(val);r eturn0;}voidshowCube(doublex){printf("Thecubeof%eis%e.\n",x,x*x*x);}Chapter 6Programming ExercisesPE 6--‐1/*pe6-1.c*//*thisimplementationassumesthecharactercodes*/ /*aresequential,astheyareinASCII.*/#include<stdio.h>#defineSIZE26intmain(void){charlcase[SIZE];inti;for(i=0;i<SIZE;i++)lcase[i]='a'+i;for(i=0;i<SIZE;i++)printf("%c",lcase[i]);printf("\n");return0;}PE 6--‐3/*pe6-3.c*//*thisimplementationassumesthecharactercodes*/ /*aresequential,astheyareinASCII.*/#include<stdio.h>intmain(void){charlet='F';charstart;charend;for(end=let;end>='A';end--){for(start=let;start>=end;start--)printf("%c",start);printf("\n");}return0;}PE 6--‐6/*pe6-6.c*/#include<stdio.h>intmain(void){intlower,upper,index;intsquare,cube;printf("Enterstartinginteger:");scanf("%d",&lower);printf("Enterendinginteger:");scanf("%d",&upper);printf("%5s%10s%15s\n","num","square","cube");for(index=lower;index<=upper;index++){square=index*index;cube=index*square;printf("%5d%10d%15d\n",index,square,cube);}return0;}PE 6--‐8/*pe6-8.c*/#include<stdio.h>intmain(void){doublen,m;doubleres;printf("Enterapairofnumbers:");while(scanf("%lf%lf",&n,&m)==2){res=(n-m)/(n*m);printf("(%.3g-%.3g)/(%.3g*%.3g)=%.5g\n",n,m,n,m,res);printf("Enternextpair(non-numerictoquit):");}return0;}PE 6--‐11/*pe6-11.c*/#include<stdio.h>#defineSIZE8intmain(void){intvals[SIZE];inti;printf("Pleaseenter%dintegers.\n",SIZE);for(i=0;i<SIZE;i++)scanf("%d",&vals[i]);printf("Here,inreverseorder,arethevaluesyouentered:\n");for(i=SIZE -1;i>=0;i--)printf("%d",vals[i]);printf("\n");return0;}PE 6--‐13/*pe6-13.c*//*Thisversionstartswiththe0power*/#include<stdio.h>#defineSIZE8intmain(void){inttwopows[SIZE];inti;intvalue=1;/*2tothe0*/for(i=0;i<SIZE;i++){twopows[i]=value;value*=2;}i=0;do{printf("%d",twopows[i]);i++;}while(i<SIZE);printf("\n");return0;}PE 6--‐14/*pe-14.c*//*ProgrammingExercise6-14*/#include<stdio.h>#defineSIZE8intmain(void){doublearr[SIZE];doublearr_cumul[SIZE];inti;printf("Enter%dnumbers:\n",SIZE);for(i=0;i<SIZE;i++){printf("value#%d:",i+1);scanf("%lf",&arr[i]);/*orscanf("%lf",arr+i);*/}arr_cumul[0]=arr[0];/*setfirstelement*/for(i=1;i<SIZE;i++) arr_cumul[i]=arr_cumul[i-1]+arr[i];for(i=0;i<SIZE;i++)printf("%8g",arr[i]);printf("\n");for(i=0;i<SIZE;i++)printf("%8g",arr_cumul[i]);printf("\n");return0;}PE 6--‐16/*pe6-16.c*/#include<stdio.h>#defineRATE_SIMP0.10#defineRATE_COMP0.05#defineINIT_AMT100.0intmain(void){doubledaphne=INIT_AMT;doubledeidre=INIT_AMT;intyears=0;while(deidre<=daphne){daphne+=RATE_SIMP*INIT_AMT;deidre+=RATE_COMP*deidre;++years;}printf("Investmentvaluesafter%dyears:\n",years);printf("D aphne:$%.2f\n",daphne);printf("Deidre:$%.2f\n",deidre);return0;}Chapter 7Programming ExercisesPE 7--‐1/*ProgrammingExercise7-1*/#include<stdio.h>intmain(void){charch;intsp_ct=0;intnl_ct=0;intother=0;while((ch=getchar())!='#'){if(ch=='')sp_ct++;elseif(ch=='\n')nl_ct++;elseother++;}printf("spaces:%d,newlines:%d,others:%d\n",sp_ct,nl_ct,other); return0;}PE 7--‐3/*ProgrammingExercise7-3*/#include<stdio.h>intmain(void){intn;doublesumeven=0.0;intct_even=0;doublesumodd=0.0;intct_odd=0;while(scanf("%d",&n)==1&&n!=0){if(n%2==0){sumeven+=n;++ct_even;}else//n%2iseither1or-1{sumodd+=n;++ct_odd;}}printf("Numberofevens:%d",ct_even);if(ct_even>0)printf("average:%g",sumeven/ct_even);putchar('\n');printf("Numberofodds:%d",ct_odd);if(ct_odd>0)printf("average:%g",sumodd/ct_odd);putchar('\n');printf("\ndone\n");return0;}PE 7--‐5/*ProgrammingExercise7-5*/#include<stdio.h>intmain(void){charch;intct1=0;intct2=0;while((ch=getchar())!='#'){switch(ch){case'.':putchar('!');++ct1;break;case'!':putchar('!');putchar('!');++ct2;break;default:putchar(ch);}}printf("%dreplacement(s)of.with!\n",ct1);printf("%dreplacement(s)of!with!!\n",ct2);return0;}PE 7--‐7//ProgrammingExercise7-7#include<stdio.h>#defineBASEPAY10//$10perhour#defineBASEHRS40//hoursatbasepay#defineOVERTIME1.5//1.5time#defineAMT1300//1stratetier#defineAMT2150//2stratetier#defineRATE10.15//ratefor1sttier#defineRATE20.20//ratefor2ndtier#defineRATE30.25//ratefor3rdtierintmain(void){doublehours;doublegross;doublenet;doubletaxes;printf("Enterthenumberofhoursworkedthisweek:");scanf("%lf",&hours);if(hours<=BASEHRS)gross=hours*BASEPAY;elsegross=BASEHRS*BASEPAY+(hours-BASEHRS)*BASEPAY*OVERTIME;if(gross<=AMT1)taxes=gross*RATE1;elseif(gross<= AMT1+AMT2)taxes=AMT1*RATE1+(gross-AMT1)*RATE2;elsetaxes=AMT1*RATE1+AMT2*RATE2+(gross-AMT1-AMT2)*RATE3;net=gross-taxes; printf("gross:$%.2f;taxes:$%.2f;net:$%.2f\n",gross,taxes,net);return0;}PE 7--‐9/*ProgrammingExercise7-9*/#include<stdio.h>#include<stdbool.h>intmain(void){intlimit;intnum;intdiv;boolnumIsPrime;//useintifstdbool.hnotavailableprintf("Enterapositiveinteger:");while(scanf("%d",&limit)==1&&limit>0){if(limit>1)printf("Herearetheprimenumbersupthrough%d\n",limit);elseprintf("Noprimes.\n");for(num=2;num<=limit;num++){for(div=2,numIsPrime=true;(div*div)<=num;div++)if(num%div==0)numIsPrime =false;if(numIsPrime)printf("%disprime.\n",num);}printf("Enterapositiveinteger(qtoquit):");}printf("Done!\n");return0;}PE 7--‐11/*pe7-11.c*//*ProgrammingExercise7-11*/#include<stdio.h>#include<ctype.h>intmain(void){constdoubleprice_artichokes=2.05;constdoubleprice_beets=1.15;constdoubleprice_carrots=1.09;constdoubleDISCOUNT_RATE=0.05;constdoubleunder5=6.50;constdoubleunder20=14.00;constdoublebase20=14.00;constdoubleextralb=0.50;charch;doublelb_artichokes=0;doublelb_beets=0;doublelb_carrots=0;doublelb_temp;doublelb_total;doublecost_artichokes;doublecost_beets;doublecost_carrots;doublecost_total;doublefinal_total;doublediscount;doubleshipping;printf("Enteratobuyartichokes,bforbeets,");printf("cforcarrots,qtoquit:");while((ch=getchar())!='q'&&ch!='Q'){if(ch=='\n')continue;while(getchar()!='\n')continue;ch=tolower(ch);switch(ch){case'a':printf("Enterpoundsofartichokes:");scanf("%lf",&lb_ temp);lb_artichokes+=lb_temp;break;case'b':printf("Enterpoundsofbeets:");scanf("%lf",&lb_temp);lb_beets+=lb_temp;break;case'c':printf("Enterpoundsofcarrots:");scanf("%lf",&lb_t emp);lb_carrots+=lb_temp;break;default:printf("%cisnotavalidchoice.\n",ch);}printf("Enteratobuyartichokes,bforbeets,");printf("cforcarrots,q toquit:");}cost_artichokes=price_artichokes*lb_artichokes;cost_beets=price_beets*lb_beets;cost_carrots=price_carrots*lb_carrots;cost_total=cost_artichokes+cost_beets+cost_carrots;lb_total=lb_artichokes+lb_beets+lb_carrots;if(lb_total<=0)shipping=0.0;elseif(lb_total<5.0)shipping=under5;elseif(lb_total<20)shipping=under20;elseshipping=base20+extralb*lb_total;if(cost_total>100.0)discount=DISCOUNT_RATE*cost_total;elsediscount=0.0;final_total=cost_total+shipping-discount;printf("Yourorder:\n");printf("%.2flbsofartichokesat$%.2fperpound:$%.2f\n",lb_artich okes,price_artichokes,cost_artichokes);printf("%.2flbsofbeetsat$%.2fperpound:$%.2f\n",lb_beets,price_beets,cost_beets);printf("%.2flbsofcarrotsat$%.2fperpound:$%.2f\n",lb_carrots,price_carrots,cost_carrots);printf("Totalcostofvegetables:$%.2f\n ",cost_total);if(cost_total>100)printf("Volumediscount:$%.2f\n",discount);printf("Shipping:$%.2f\n",shipping);printf("Totalcharges:$%.2f\n",final_total);return0;}Chapter 8Programming ExercisesPE 8--‐1/*ProgrammingExercise8-1*/#include<stdio.h>intmain(void){intch;intct=0;while((ch=getchar())!=EOF)ct++;printf("%dcharactersread\n",ct);return0;}PE 8--‐3/*ProgrammingExercise8-3*//*Usingctype.heliminatesneedtoassumeconsecutivecoding*/#include<stdio.h>#include<ctype.h>intmain(void){intch;unsignedlonguct=0;unsignedlonglct=0;unsignedlongoct=0;while((ch=getchar())!=EOF)if(isupper(ch))uct++;elseif(islower(ch))lct++;elseoct++;printf("%luuppercasecharactersread\n",uct);printf("%lulowercas echaractersread\n",lct);printf("%luothercharactersread\n",oct);return0;}/*oryoucoulduseif(ch>='A'&&ch<='Z')uct++;elseif(ch>='a'&&ch<='z')lct++;elseoct++;*/PE 8--‐5/*ProgrammingExercise8-5*//*binaryguess.c--animprovednumber-guesser*//*butreliesupontruthful,correctresponses*/#include<stdio.h>#include<ctype.h>intmain(void){inthigh=100;intlow=1;intguess=(high+low)/2;charresponse;printf("Pickanintegerfrom1to100.Iwilltrytoguess");printf("it.\nRespondw ithayifmyguessisright,with");printf("\nahifitishigh,andwithanlifitislow .\n");printf("Uh...isyournumber%d\n",guess);while((response=getchar())!='y')/*getresponse*/{if(response=='\n')continue;if(response!='h'&&response!='l')printf("Idon'tunderstandthatresponse.Pleaseenterhfor\n");printf("high,lfor low,oryforcorrect.\n");continue;}if(response=='h')high=guess-1;elseif(response=='l')low=guess+1;guess=(high+low)/2;printf("Well,then,isit%d\n",guess);}printf("IknewIcoulddoit!\n");return0;}PE 8--‐7/*ProgrammingExercise8-7*/#include<stdio.h>#include<ctype.h>#include<stdio.h>#defineBASEPAY18.75//$8.75perhour#defineBASEPAY29.33//$9.33perhour#defineBASEPAY310.00//$10.00perhour#defineBASEPAY411.20//$11.20perhour#defineBASEHRS40//hoursatbasepay#defineOVERTIME1.5//1.5time#defineAMT1300//1stratetier#defineAMT2150//2stratetier#defineRATE10.15//ratefor1sttier#defineRATE20.20//ratefor2ndtier#defineRATE30.25//ratefor3rdtierintgetfirst(void);voidmenu(void);intmain(void){doublehours;doublegross;doublenet;doubletaxes;doublepay;charresponse;menu();while((response=getfirst())!='q'){if(response=='\n')/*skipovernewlines*/continue;response=tolower(response);/*acceptAasa,etc.*/switch(response){case'a':pay=BASEPAY1;break;case'b':pay=BASEPAY2;break;case'c':pay=BASEPAY3;break;case'd':pay=BASEPAY4;break;default:printf("Pleaseentera,b,c,d,orq.\n");menu();continue;//gotobeginningofloopprintf("Enterthenumberofhoursworkedthisweek:");scanf("%lf",&hours);if(hours<=BASEHRS)gross=hours*pay;elsegross=BASEHRS*pay+(hours-BASEHRS)*pay*OVERTIME;if(gross<=AMT1)taxes=gross*RATE1;elseif(gross<= AMT1+AMT2)taxes=AMT1*RATE1+(gross-AMT1)*RATE2;elsetaxes=AMT1*RATE1+AMT2*RATE2+(gross-AMT1-AMT2)*RATE3;net=gross-taxes; printf("gross:$%.2f;taxes:$%.2f;net:$%.2f\n",gross,taxes,net);menu();} printf("Done.\n");return0;}voidmenu(void){printf("********************************************************""*********\n");printf("Enterthelettercorrespondingtothedesiredpayrate""oraction:\n");printf("a)$%4.2f/hrb)$%4.2f/hr\n",BASEPAY1,BASEPAY2);printf("c)$%5.2f/hrd)$%5.2f/hr\n",BASEPAY3,BASEPAY4);printf("q)quit\n");printf("********************************************************""*********\n");}intgetfirst(void){intch;ch=getchar();while(isspace(ch))ch=getchar();while(getchar()!='\n')continue;returnch;}Chapter 9Programming ExercisesPE 9--‐1/*ProgrammingExercise9-1*/#include<stdio.h>doublemin(double,double);intmain(void){doublex,y;printf("Entertwonumbers(qtoquit):");while(scanf("%lf%lf",&x,&y)==2){printf("Thesmallernumberis%f.\n",min(x,y));printf("Nexttwovalues(qtoquit):");}printf("Bye!\n");return0;}doublemin(doublea,doubleb){returna<ba:b;}/*alternativeimplementationdoublemin(doublea,doubleb){if(a<b)returna;elsereturnb;}*/PE 9--‐3/*ProgrammingExercise9-3*/#include<stdio.h>voidchLineRow(charch,intc,intr);intmain(void){charch;intcol,row;printf("Enteracharacter(#toquit):");while((ch=getchar())!='#'){if(ch=='\n')continue;printf("Enternumberofcolumnsandnumberofrows:");if(scanf("%d%d" ,&col,&row)!=2)break;chLineRow(ch,col,row);printf("\nEnternextcharacter(#toquit):");}printf("Bye!\n");return0;}//startrowsandcolsat0voidchLineRow(charch,intc,intr){intcol,row;for(row=0;row<r;row++){for(col=0;col<c;col++)putchar(ch);putchar('\n');}return;}PE 9--‐5/*ProgrammingExercise9-5*/#include<stdio.h>voidlarger_of(double*p1,double*p2);intmain(void){doublex,y;printf("Entertwonumbers(qtoquit):");while(scanf("%lf%lf",&x,&y)==2){larger_of(&x,&y);printf("Themodifiedvaluesare%fand%f.\n",x,y);printf("Nexttwovalues(qtoq uit):");}printf("Bye!\n");return0;}voidlarger_of(double*p1,double*p2){if(*p1>*p2)*p2=*p1;else*p1=*p2;}//alternatively:/*voidlarger_of(double*p1,double*p2){*p1=*p2=*p1>*p2*p1:*p2;}*/PE 9--‐8/*ProgrammingExercise9-8*/#include<stdio.h>doublepower(doublea,intb);/*ANSIprototype*/intmain(void){doublex,xpow;intn;printf("Enteranumberandtheintegerpower");printf("towhich\nthenumberwillberaised.Enterq");printf("toquit.\n");while(scanf("%lf%d",&x,&n)==2){xpow=power(x,n);/*functioncall*/printf("%.3gtothepower%dis%.5g\n",x,n,xpow);printf("Enternextpairofnumbersorqtoquit.\n");}printf("Hopeyouenjoyedthispowertrip--bye!\n");return0;}doublepower(doublea,intb)/*functiondefinition*/{doublepow=1;inti;if(b==0){if(a==0)printf("0tothe0undefined;using1asthevalue\n");pow=1.0;}elseif(a==0)pow=0.0;elseif(b>0)for(i=1;i<=b;i++)pow*=a;else/*b<0*/pow=1.0/power(a,-b);returnpow;/*returnthevalueofpow*/}PE 9--‐10/*ProgrammingExercise9-10*/#include<stdio.h>voidto_base_n(intx,intbase);intmain(void){intnumber;intb;intcount;printf("Enteraninteger(qtoquit):\n");while(scanf("%d",&number)==1){printf("Enternumberbase(2-10):");while((count=scanf("%d",&b))==1&&(b<2||b>10)){printf("baseshouldbeintherange2-10:");}if(count!=1)break;printf("Base%dequivalent:",b);to_base_n(number,b);putchar('\n');printf("Enteraninteger(qtoquit):\n");}printf("Done.\n");return0;}voidto_base_n(intx,intbase)/*recursivefunction*/{intr;r=x%base;if(x>=base)to_base_n(x/base,base);putchar('0'+r);return;}Chapter 10 Programming ExercisesPE 10--‐1/*ProgrammingExercise10-1*/#include<stdio.h>#defineMONTHS12//numberofmonthsinayear#defineYRS5// numberofyearsofdataintmain(void){//initializingrainfalldatafor2010-2014constfloatrain[YRS][MONTHS]={{4.3,4.3,4.3,3.0,2.0,1.2,0.2,0.2,0.4,2.4,3.5,6.6},{8.5,8.2,1.2,1.6,2.4,0.0,5.2,0.9,0.3,0.9,1.4,7.3},{9.1,8.5,6.7,4.3,2.1,0.8,0.2,0.2,1.1,2.3,6.1,8.4},{7.2,9.9,8.4,3.3,1.2,0.8,0.4,0.0,0.6,1.7,4.3,6.2},{7.6,5.6,3.8,2.8,3.8,0.2,0.0,0.0,0.0,1.3,2.6,5.2}};intyear,month;floatsubtot,total;printf("YEARRAINFALL(inches)\n");for(year=0,total=0;year<YRS;year++){/*foreachyear,sumrainfallforeachmonth*/for(month=0,subtot=0;mont h<MONTHS;month++)subtot+=*(*(rain+year)+month);printf("%5d%15.1f\ n",2010+year,subtot);total+=subtot;/*totalforallyears*/}printf("\nTheyearlyaverageis%.1finches.\n\n",total/YRS);printf("MONTHLY AVERAGES:\n\n");printf("JanFebMarAprMayJunJulAugSepOct");printf("NovDec\n");for(month=0;month<MONTHS;month++){/*foreachmonth,sumrainfalloveryears*/for(year=0,subtot=0;year<YRS;year++)subtot+=*(*(rain+year)+month);printf("%4.1f",subtot/YRS);}printf("\n");return0;}PE 10--‐3/*ProgrammingExercise10-3*/#include<stdio.h>#defineLEN10intmax_arr(constintar[],intn);voidshow_arr(constintar[],intn);intmain(void){intorig[LEN]={1,2,3,4,12,6,7,8,9,10};intmax;show_arr(orig,LEN);max=max_arr(orig,LEN);printf("%d=largestvalue\n",max);return0;}intmax_arr(constintar[],intn){inti;intmax=ar[0];/*don'tuse0asinitialmaxvalue--failsifallarrayvaluesareneg*/for(i=1;i<n;i++)if(max<ar[i])max=ar[i];returnmax;}voidshow_arr(constintar[],intn){inti;for(i=0;i<n;i++)printf("%d",ar[i]);putchar('\n');}PE 10--‐5/*ProgrammingExercise10-5*/#include<stdio.h>#defineLEN10doublemax_diff(constdoublear[],intn);voidshow_arr(constdoublear[],intn);intmain(void){doubleorig[LEN]={1.1,2,3,4,12,61.3,7,8,9,10};doublemax;show_arr(orig,LEN);max=max_diff(orig,LEN);printf("%g=maximumdifference\n",max);return0;}doublemax_diff(constdoublear[],intn){inti;doublemax=ar[0];doublemin=ar[0];for(i=1;i<n;i++){if(max<ar[i])max=ar[i];elseif(min>ar[i])min=ar[i];}returnmax-min;}voidshow_arr(constdoublear[],intn){inti;for(i=0;i<n;i++)printf("%g",ar[i]);putchar('\n');}PE 10--‐8/*ProgrammingExercise10-8*/#include<stdio.h>#defineLEN17#defineLEN23voidcopy_arr(intar1[],constintar2[],intn);voidshow_arr (constint[],int);intmain(void){intorig[LEN1]={1,2,3,4,5,6,7};intcopy[LEN2];show_arr(orig,LEN1);copy_arr(copy,orig+2,LEN2);show_arr(copy,LEN2);return0;}voidcopy_arr(intar1[],constintar2[],intn){inti;for(i=0;i<n;i++)ar1[i]=ar2[i];}voidshow_arr(constintar[],intn){inti;for(i=0;i<n;i++)printf("%d",ar[i]);putchar('\n');}PE 10--‐11/*ProgrammingExercise10-11*/#include<stdio.h>#defineROWS3#defineCOLS5voidtimes2(intar[][COLS],intr);voidshowarr2(intar[][COLS],intr);intmain(void){intstuff[ROWS][COLS]={{1,2,3,4,5},{6,7,8,-2,10},{11,12,13,14,15}};showarr2(stuff,ROWS);putchar('\n');times2(stuff,ROWS);showarr2(stuff,ROWS);return0;}voidtimes2(intar[][COLS],intr){introw,col;for(row=0;row<r;row++)for(col=0;col<COLS;col++)ar[row][col]*=2;}voidshowarr2(intar[][COLS],intr){introw,col;for(row=0;row<r;row++){for(col=0;col<COLS;col++)printf("%d",ar[row][col]);putchar('\n');}}PE 10--‐14/*ProgrammingExercise10-14*/#include<stdio.h>#defineROWS3#defineCOLS5voidstore(doublear[],intn);doubleaverage2d(introws,intcols,doublear[rows][cols]);doublemax2d(introws,intcols,doublear[rows][cols]);voidshowarr2(introws,intcols,doublear[rows][cols]);doubleaverage(constdoublear[],intn);intmain(void){doublestuff[ROWS][COLS];introw;for(row=0;row<ROWS;row++){printf("Enter%dnumbersforrow%d\n",COLS,row+1);store(stuff[row],COLS);}printf("arraycontents:\n");showarr2(ROWS,COLS,stuff);for(row=0;row<ROWS;row++)printf("averagevalueofrow%d=%g\n",row+1,average(stuff[row],COLS));printf("averagev alueofallrows=%g\n",average2d(ROWS,COLS,stuff));printf("largestvalue=%g\n",max2d(R OWS,COLS,stuff));printf("Bye!\n");return0;}voidstore(doublear[],intn){inti;for(i=0;i<n;i++){printf("Entervalue#%d:",i+1);scanf("%lf",&ar[i]);}}doubleaverage2d(introws,intcols,doublear[rows][cols]) {intr,c;doublesum=0.0;for(r=0;r<rows;r++)for(c=0;c<cols;c++)sum+=ar[r][c];if(rows*cols>0)returnsum/(rows*cols);elsereturn0.0;}doublemax2d(introws,intcols,doublear[rows][cols]) {intr,c;doublemax=ar[0][0];for(r=0;r<rows;r++)for(c=0;c<cols;c++)if(max<ar[r][c])max=ar[r][c];returnmax;}voidshowarr2(introws,intcols,doublear[rows][cols]) {introw,col;for(row=0;row<rows;row++){for(col=0;col<cols;col++)printf("%g",ar[row][col]);putchar('\n');}}doubleaverage(constdoublear[],intn){inti;doublesum=0.0;for(i=0;i<n;i++)sum+=ar[i];if(n>0)returnsum/n;elsereturn0.0;}Chapter 11 Programming ExercisesPE 11--‐1/*ProgrammingExercise11-1*/#include<stdio.h>#defineLEN10char*getnchar(char*str,intn);intmain(void){charinput[LEN];char*check;check=getnchar(input,LEN-1);if(check==NULL)puts("Inputfailed.");elseputs(input);puts("Done.\n");return0;}。

cprimerplus习题答案

cprimerplus习题答案

cprimerplus习题答案cprimerplus习题答案C Primer Plus是一本经典的C语言教材，被广泛用于学习和教授C语言的人士。

这本书的习题是帮助读者巩固所学知识和提高编程能力的重要环节。

在这篇文章中，我将为大家提供一些C Primer Plus习题的答案，希望对正在学习C语言的读者有所帮助。

1. 习题1：编写一个程序，输出"Hello, World!"。

答案：```c#include <stdio.h>int main() {printf("Hello, World!");return 0;}```这是一个非常简单的程序，使用了C语言的标准库函数printf()来输出字符串。

2. 习题2：编写一个程序，输入两个整数，然后计算它们的和并输出。

答案：```c#include <stdio.h>int main() {int num1, num2, sum;printf("请输入两个整数：");scanf("%d %d", &num1, &num2);sum = num1 + num2;printf("它们的和是：%d", sum);return 0;}```这个程序使用了scanf()函数来接收用户输入的两个整数，并使用加法运算符计算它们的和，最后使用printf()函数输出结果。

3. 习题3：编写一个程序，输入一个整数，然后判断它是否为偶数并输出结果。

答案：```c#include <stdio.h>int main() {int num;printf("请输入一个整数：");scanf("%d", &num);if (num % 2 == 0) {printf("这是一个偶数。

【C++PrimerPlus】编程练习答案——第12章

【C++PrimerPlus】编程练习答案——第12章

【C++PrimerPlus】编程练习答案——第12章 1// chapter12_1_cow.h234 #ifndef LEARN_CPP_CHAPTER12_1_COW_H5#define LEARN_CPP_CHAPTER12_1_COW_H67class Cow {8private:9char name_[20];10char * hobby_;11double weight_;12public:13 Cow();14 Cow(const char * name, const char * hobby, double weight);15 Cow(const Cow & c);16 ~Cow();17 Cow & operator=(const Cow & c);18void showcow() const;19 };202122#endif//LEARN_CPP_CHAPTER12_1_COW_H232425// chapter12_1_cow.cpp2627 #include "chapter12_1_cow.h"28 #include <cstring>29 #include <iostream>3031 Cow::Cow() {32 name_[0] = '\0';33 hobby_ = nullptr;34 weight_ = 0;35 }3637 Cow::Cow(const char * name, const char * hobby, double weight) {38 strcpy(name_, name);39 hobby_ = new char[strlen(hobby)];40 strcpy(hobby_, hobby);41 weight_ = weight;42 }4344 Cow::Cow(const Cow &c) {45 strcpy(name_, _);46if (!hobby_) delete [] hobby_;47 hobby_ = new char[strlen(c.hobby_)];48 strcpy(hobby_, c.hobby_);49 weight_ = c.weight_;50 }5152 Cow::~Cow() {53delete [] hobby_;54 }5556 Cow & Cow::operator=(const Cow & c) {57 strcpy(name_, _);58if (!hobby_) delete [] hobby_;59 hobby_ = new char[strlen(c.hobby_)];60 strcpy(hobby_, c.hobby_);61 weight_ = c.weight_;62return *this;63 }6465void Cow::showcow() const {66using namespace std;67 cout << "name: " << name_ << endl68 << "hobby: " << hobby_ << endl69 << "weight: " << weight_ << endl;70 }7172// run7374void ch12_1() {75 Cow a("nma", "tennis", 70);76 Cow b("nmb", "football", 65);77 a.showcow();78 b.showcow();79 b = a;80 b.showcow();81 Cow c(a);82 c.showcow();83 }// chapter12_2_string2.h#ifndef LEARN_CPP_CHAPTER12_2_STRING2_H#define LEARN_CPP_CHAPTER12_2_STRING2_H#include <iostream>using std::istream;using std::ostream;class string2 {private:char * str;int len;static int num_strings;static const int CINLIM = 80;public:string2();string2(const string2 & s);string2(const char * s);~string2();int length() const {return len;}int charnum(char ch) const; // dstring2 & stringlow(); // bstring2 & stringup(); // cstring2 & operator=(const string2 & s);string2 & operator=(const char * s);char & operator[](int i);const char & operator[](int i) const;friend bool operator<(const string2 & s1, const string2 & s2); friend bool operator>(const string2 & s1, const string2 & s2); friend bool operator==(const string2 & s1, const string2 & s2); friend ostream & operator<<(ostream & os, const string2 & s); friend istream & operator>>(istream & is, string2 & s);friend string2 & operator+(string2 & s1, const string2 & s2); // a static int howmany();};#endif//LEARN_CPP_CHAPTER12_2_STRING2_H// chapter12_2_string2.cpp#include "chapter12_2_string2.h"#include <cstring>#include <cctype>int string2::num_strings = 0;string2::string2() {len = 4;str = new char[1];str[0] = '\0';++ num_strings;}string2::string2(const string2 &s) {len = s.length();str = new char[len + 1];std::strcpy(str, s.str);++ num_strings;}string2::string2(const char *s) {len = std::strlen(s);str = new char[len + 1];std::strcpy(str, s);++ num_strings;}string2::~string2() {delete [] str;-- num_strings;}string2 &string2::operator=(const string2 &s) {if (this == &s)return *this;delete [] str;len = s.length();str = new char[len + 1];std::strcpy(str, s.str);return *this;}string2 &string2::operator=(const char *s) {delete [] str;len = std::strlen(s);str = new char[len + 1];std::strcpy(str, s);return *this;}char &string2::operator[](int i) {return str[i];}const char &string2::operator[](int i) const {return str[i];}int string2::howmany() {return num_strings;}bool operator<(const string2 & s1, const string2 & s2) { return (std::strcmp(s1.str, s2.str) < 0);}bool operator>(const string2 & s1, const string2 & s2) { return s2 < s1;}bool operator==(const string2 & s1, const string2 & s2) { return (std::strcmp(s1.str, s2.str) == 0);}ostream & operator<<(ostream & os, const string2 & s) { os << s.str;return os;}istream & operator>>(istream & is, string2 & s) {char temp[string2::CINLIM];is.get(temp, string2::CINLIM);if (is)s = temp;while (is && is.get() != '\n')continue;return is;}int string2::charnum(char ch) const {int i = 0, num = 0;while (str[i] != '\0') {if (str[i] == ch)++ num;++ i;}return num;}string2 &string2::stringlow() {int i = 0;while (str[i] != '\0') {if (std::isalpha(str[i]))str[i] = std::toupper(str[i]);++ i;}return *this;}string2 &string2::stringup() {int i = 0;while (str[i] != '\0') {if (std::isalpha(str[i]))str[i] = std::tolower(str[i]);++ i;}}string2 & operator+(string2 & s1, const string2 & s2) {char * temp = new char[s1.len];std::strcpy(temp, s1.str);delete [] s1.str;s1.str = new char[s1.len + s2.len + 1];s1.len += s2.len;std::strcpy(s1.str, temp);std::strcat(s1.str, s2.str);return s1;}// runvoid ch12_2() {using namespace std;string2 s1(" and I am a C++ student.");string2 s2 = "Please enter your name: ";string2 s3;cout << s2;cin >> s3;string2 t("My name is ");s2 = t + s3;cout << s2 << ".\n";s2 = s2 + s1;s2.stringup();cout << "The string\n" << s2 << "\ncontains " << s2.charnum('A')<< " 'A' characters in it.\n";s1 = "red";string2 rgb[3] = {string2(s1), string2("green"), string2("blue")};cout << "Enter the name of a primary color for mixing light: ";string2 ans;bool success = false;while (cin >> ans) {ans.stringlow();for (int i = 0; i < 3; ++ i) {if (ans == rgb[i]) {cout << "That's right!\n";success = true;break;}}if (success)break;elsecout << "Try again!\n";}cout << "Bye\n";}1// chapter12_3_stock.h234void ch12_2() {5using namespace std;6 string2 s1(" and I am a C++ student.");7 string2 s2 = "Please enter your name: ";8 string2 s3;9 cout << s2;10 cin >> s3;11 string2 t("My name is ");12 s2 = t + s3;13 cout << s2 << ".\n";14 s2 = s2 + s1;15 s2.stringup();16 cout << "The string\n" << s2 << "\ncontains " << s2.charnum('A')17 << " 'A' characters in it.\n";18 s1 = "red";19 string2 rgb[3] = {string2(s1), string2("green"), string2("blue")};20 cout << "Enter the name of a primary color for mixing light: ";21 string2 ans;22bool success = false;23while (cin >> ans) {24 ans.stringlow();25for (int i = 0; i < 3; ++ i) {26if (ans == rgb[i]) {27 cout << "That's right!\n";28 success = true;29break;30 }31 }32if (success)34else35 cout << "Try again!\n";36 }37 cout << "Bye\n";38 }394041// chapter12_3_stock.cpp4243 #include "chapter12_3_stock.h"4445 #include <iostream>46 #include <cstring>4748 stock::stock() {49 company = new char[8];50 len = 7;51 strcpy(company, "no name");52 shares = 0;53 share_val = 0.0;54 total_val = 0.0;55 }5657 stock::stock(const char * co, long n, double pr) {58 len = strlen(co);59 company = new char[len + 1];60 strcpy(company, co);61if (n < 0) {62 std::cout << "Number of shares can't be negative; "63 << company << " shares set to 0.\n";64 shares = 0;65 }66else67 shares = n;68 share_val = pr;69 set_tot();70 }7172 stock::~stock() {73delete [] company;74 }7576void stock::buy(long num, double price) {77if (num < 0) {78 std::cout << "Number of shares purchased can't be nagetive. "79 << "Transaction is aborted.\n";80 }81else {82 shares += num;83 share_val = price;84 set_tot();85 }86 }8788void stock::sell(long num, double price) {89using std::cout;90if (num < 0) {91 cout << "Number of shares sold can't be negative. "92 << "Transaction is aborted.\n";93 }94else {95 shares -= num;96 share_val = price;97 set_tot();98 }99 }100101void stock::update(double price) {102 share_val = price;103 set_tot();104 }105106void stock::show() const {107using std::cout;108using std::ios_base;109 ios_base::fmtflags orig = cout.setf(ios_base::fixed, ios_base::floatfield); 110 std::streamsize prec = cout.precision(3);111 cout << "Company: " << company112 << " Shares: " << shares << '\n';113 cout << "Shares Prices: $" << share_val << '\n';114 cout.precision(2);115 cout << "Total Worth: $" << total_val << '\n';116 cout.setf(orig, ios_base::floatfield);117 cout.precision(prec);118 }119120const stock &stock::topval(const stock &s) const {121if (s.total_val > total_val)122return s;123return *this;124 }125126 std::ostream &operator<<(std::ostream & os, const stock & s) { 127 os << "Company: " << pany128 << " Shares: " << s.shares << '\n';129 os << "Shares Prices: $" << s.share_val << '\n';130 os.precision(2);131 os << "Total Worth: $" << s.total_val << '\n';132 }133134135// run136137138139void ch12_3() {140using namespace std;141const int STKS = 4;142 stock ss[STKS] = {143 stock("NanoSmart", 12, 20.0),144 stock("Boffo Objects", 200, 2.0),145 stock("Monolithic Obelisks", 130, 3.25),146 stock("Fleep Enterprises", 60, 6.5)147 };148 cout << "Stock holdings: \n";149int st;150for (st = 0; st < STKS; ++ st)151 cout << ss[st];152const stock * top = &ss[0];153for (st = 1; st < STKS; ++ st)154 top = &top -> topval(ss[st]);155 cout << "\nMost valuable holding:\n";156 cout << *top;157 }1// chapter12_4_stack.h234 #ifndef LEARN_CPP_CHAPTER12_4_STACK_H5#define LEARN_CPP_CHAPTER12_4_STACK_H67 typedef unsigned long Item;89class Stack {10private:11enum {MAX = 10};12 Item * pitems;13int size;14int top;15public:16 Stack(int n = MAX);17 Stack(const Stack & st);18 ~Stack();19bool isempty() const;20bool isfull() const;21bool push(const Item & item);22bool pop(Item & item);23void show() const;24 Stack & operator=(const Stack & st);25 };2627282930#endif//LEARN_CPP_CHAPTER12_4_STACK_H3132// chapter12_4_stack.cpp3334 #include "chapter12_4_stack.h"35 #include <iostream>3637 Stack::Stack(int n) {38 pitems = new Item[n];39 size = n;40 top = 0;41 }4243 Stack::Stack(const Stack &st) {44 pitems = new Item[st.size];45 size = st.size;46 top = st.top;47for (int i = 0; i < st.top; ++ i)48 pitems[i] = st.pitems[i];49 }5051 Stack::~Stack() {52delete [] pitems;53 }5455bool Stack::isempty() const {56if (top == 0)57return true;58return false;59 }6061bool Stack::isfull() const {62if (top == size)63return true;64return false;65 }6667bool Stack::push(const Item &item) {68if (isfull())69return false;70 pitems[top ++] = item;71return true;72 }7374bool Stack::pop(Item &item) {75if (isempty())76return false;77 item = pitems[-- top];78return true;79 }8081 Stack &Stack::operator=(const Stack &st) { 82if (this == &st)83return *this;84if (pitems)85delete [] pitems;86 pitems = new Item[st.size];87 size = st.size;88 top = st.top;89for (int i = 0; i < st.top; ++ i)90 pitems[i] = st.pitems[i];91return *this;92 }9394void Stack::show() const {95using namespace std;96 cout << "Stack: ";97for (int i = 0; i < top; ++ i)98 cout << pitems[i] << "";99 cout << endl;100 }101102// run103104void ch12_4() {105 Stack s1(15);106 s1.show();107 s1.push(1234);s1.push(123);s1.push(12); 108 s1.show();109 Item t = 0;110 s1.pop(t);111 s1.show();112113 Stack s2(s1);114 s2.show();115 s2.push(12345);116 s2.show();117118 Stack s3 = s1;119 s3.show();120 s3.pop(t);121 s3.show();122 }// ch12_5&6// 待更新欢迎⼤家⼀起交流。

C++primer plus章节练习答案-第4章

C++primer plus章节练习答案-第4章

/*****************************************************/ //practice_8 #include <iostream> const int ArSize = 50; struct Pizza {
char company[ArSize]; double diameter; double weight; }; int main() { using namespace std; Pizza * pp=new Pizza; cout << "Enter the information in a kind of pizza.\n "; cout << "Enter the diameter(in inch): "; cin >> pp->diameter; cin.get(); //读取并丢弃输入数字时按下回车键留在输入流中的换行符 cout << "Enter company: "; cin.getline(pp->company, ArSize); cout << "Enter the weight(in g): "; cin >> pp->weight;
/*****************************************************/
//practice_3
//题目要求把姓、名和逗号、空格组合后，存储并显示，
//所以需要三个变量，其中2个分别用来接收用户输入的姓
//和名，另一个变量用来存储组合后的全名
#include <iostream>