JAVA语⾔程序设计基础课后习题第五章//exercise 5.1package fivechapterexercise1;public class first {public static void main(String[] args) {// TODO Auto-generated method stubfinal int NUMBER_OF_PENTAGONAL_PER_LINE=10;for(int i=1;i<=100;i++){System.out.print(getpentagonalnumber(i)+" ");if(i%NUMBER_OF_PENTAGONAL_PER_LINE==0)System.out.println();}}public static int getpentagonalnumber(int i){return i*(3*i-1)/2;}}//exercise 5.2package fivechapterexercise1;import java.util.Scanner;public class second {public static void main(String[] args) {// TODO Auto-generated method stubScanner in=new Scanner(System.in);System.out.print("input a integer :");int integer=in.nextInt();System.out.println("The sum of digits is "+getsumdigits(integer));}public static int getsumdigits(int integer){int sum=0;while(integer!=0){sum += integer%10;integer /=10;}return sum;}}//exercise 5.3package fivechapterexercise1;import java.util.Scanner;public class third {public static void main(String[] args) {// TODO Auto-generated method stubScanner in=new Scanner(System.in);System.out.print("please input a integer:");int integer=in.nextInt();System.out.println("This integer is a palindrome?"+ispalindrome(integer));}public static boolean ispalindrome(int integer){if(integer==reverse(integer))return true;elsereturn false;}public static int reverse(int integer){int count=0;int temp=integer;while(integer!=0){integer /=10;count++;}int sum=0;for(int i=count;i>=1;i--){sum=sum+(int)(Math.pow(10, i-1))*(temp%10);temp /= 10;}return sum;}}//exercise 5.4package fivechapterexercise1;import java.util.Scanner;public class fourth {public static void main(String[] args) {// TODO Auto-generated method stubScanner in=new Scanner(System.in);System.out.print("please input integer:");int integer=in.nextInt();System.out.print("The palindrome is:"+reverse(integer));}public static int reverse(int integer){int count=0;int temp=integer;while(integer!=0){integer /=10;count++;}int sum=0;for(int i=count;i>=1;i--){sum=sum+(int)(Math.pow(10, i-1))*(temp%10);temp /= 10;}return sum;}}//exercise 5.5package fivechapterexercise1;public class fifth {public static void main(String[] args) {// TODO Auto-generated method stubdisplaySortedNumbers(4.4,2.4,9.8);}public static void displaySortedNumbers(double num1,double num2,double num3){if(num1>num2){double temp=num1;num1=num2;num2=temp;}if(num1>num3){double temp=num1;num1=num3;num3=temp;}if(num2>num3){double temp=num2;num2=num3;num3=temp;}System.out.println("Ascending order number three:"+num1+","+num2+","+num3+"."); }}//exercise 5.6package fivechapterexercise1;public class sixth {public static void main(String[] args) {// TODO Auto-generated method stubdisplayPattern(15);}public static void displayPattern(int n){for(int i=1;i<=n;i++){for(int j=i+1;j<=n;j++){System.out.print(" ");}for(int j=i;j>=1;j--){System.out.printf("%3d", j);}System.out.println();}}}//exercise 5.7package fivechapterexercise1;import java.util.Scanner;public class seventh {public static void main(String[] args) {// TODO Auto-generated method stubScanner in=new Scanner(System.in);System.out.print("input investment amount and annually interest rate:");int investmentAmount=in.nextInt();double annuallyInterestrate=in.nextDouble()/1200;System.out.println("Years\tFuture Value");for(int i=1;i<=30;i++){System.out.println(i+" \t"+futureInvestmentValue(investmentAmount,annuallyInterestrate,i));}}public static double futureInvestmentValue(double investmentAmount,double monthlyInterestRate,int years){double futureinvestmentValue=investmentAmount*(Math.pow((1+monthlyInterestRate),years));return futureinvestmentValue;}}//exercise 5.8package fivechapterexercise1;public class eighth {public static void main(String[] args) {// TODO Auto-generated method stubdouble celsius=40.0;double fahrenheit=120.0;System.out.println("摄⽒度\t华⽒度\t 华⽒度\t摄⽒度");for(int i=1;i<=10;i++){System.out.println(celsius+"\t"+((int)(celsiustofahrenheit(celsius)*10)/10.0)+"\t "+ fahrenheit+" "+((int)(fahrenheittocelsius(fahrenheit)*10)/10.0));celsius--;fahrenheit -=10;}}public static double celsiustofahrenheit(double celsius){return (9.0/5)*celsius+32;}public static double fahrenheittocelsius(double fahrenheit){return (fahrenheit-32)/(9.0/5);}}//exercise 5.9package fivechapterexercise1;public class ninth {public static void main(String[] args) {// TODO Auto-generated method stubdouble celsius=1.0;double fahrenheit=20.0;System.out.println("英尺\t⽶\t ⽶\t英尺");for(int i=1;i<=10;i++){System.out.println(celsius+"\t"+((int)(celsiustofahrenheit(celsius)*10)/10.0)+"\t "+ fahrenheit+" "+((int)(fahrenheittocelsius(fahrenheit)*10)/10.0));celsius++;fahrenheit +=5;}}public static double celsiustofahrenheit(double celsius){return celsius*0.305;}public static double fahrenheittocelsius(double fahrenheit){return (fahrenheit/0.305);}}//exercise 5.10package fivechapterexercise1;import fivechapter1.seventh;public class tenth {public static void main(String[] args) {// TODO Auto-generated method stubint count=0;for(int i=1;i<=10000;i++){if(seventh.isPrime(i))count++;}System.out.println("The number of prime is "+ count);}}//exercise 5.11package fivechapterexercise2;public class first {public static void main(String[] args) {// TODO Auto-generated method stubSystem.out.println("销售总额\t\t酬⾦");int salesamount=10000;for(int i=1;i<20;i++){System.out.println(salesamount+"\t\t"+computecommission(salesamount));salesamount+=5000;}}public static double computecommission(double salesamount){if(salesamount<5000)return salesamount*0.08;else if(salesamount<10000)return 5000*0.08+(salesamount-5000)*0.10;elsereturn 5000*0.08+5000*0.10+(salesamount-10000)*0.12;}}//exercise 5-12package fivechapterexercise2;public class second {public static void main(String[] args) {// TODO Auto-generated method stubprintChars('1','Z',10);}public static void printChars(char ch1,char ch2,int numberPerLine){int number=ch2-ch1+1;final int NUMBER_OF_CHARS_PER_LINE=numberPerLine;for(int i=0;i<number;i++){System.out.print((char)(ch1+i)+" ");if((i+1)%NUMBER_OF_CHARS_PER_LINE==0) System.out.println();}}}//exercise 5.13package fivechapterexercise2;public class third {public static void main(String[] args) {// TODO Auto-generated method stubSystem.out.println("i\t\tm(i)");for(int i=1;i<=20;i++){System.out.println(i+"\t\t"+m(i));}}public static double m(double integer){double sum=0;for(int i=1;i<=integer;i++){sum=sum+(double)i/(i+1);}return sum;}}//exercise 5-14package fivechapterexercise2;public class fourth {public static void main(String[] args) {// TODO Auto-generated method stubSystem.out.println("i\t\tm(i)");int number=10;for(int i=1;i<=10;i++){System.out.println(number+"\t\t"+m(number)); number +=10;}}public static double m(int integer){double sum=0;for(int i=1;i<=integer+1;i++){sum =sum+(Math.pow(-1,i-1)*(1.0/(2*i-1)));}return 4*sum;}}//exercise 5.17package fivechapterexercise2;public class seventh {public static void main(String[] args) {// TODO Auto-generated method stubprintMatrix(3);}public static void printMatrix(int n){for(int i=1;i<=n;i++){for(int j=1;j<=n;j++){System.out.print((int)(Math.random()*2)+" "); }System.out.println();}}}//exercise 5.18package fivechapterexercise2;public class eighth {public static void main(String[] args) {// TODO Auto-generated method stubSystem.out.println("number\t\tsqir");for(int i=0;i<=10;i++){System.out.println(2*i+"\t\t"+Math.sqrt(2*i));}}}//exercise 5-19package fivechapterexercise2;public class ninth {public static void main(String[] args) {// TODO Auto-generated method stubdouble side1=2,side2=3,side3=4;System.out.println("side1=2,side2=3,side3=4 is a triangle?"+isvalid(side1,side2,side3));}public static boolean isvalid(double side1,double side2,double side3){if(side1<side2){double temp=side1;side1=side2;side2=temp;}if(side1<side3){double temp=side1;side1=side3;side3=temp;}if(side1<side2+side3)return true;elsereturn false;}public static double area(double side1,double side2,double side3){double s=(side1+side2+side3)/2;//calculation areadouble area=Math.pow(s*(s-side1)*(s-side2)*(s-side3),0.5);return area;}}//exercise 5-20package fivechapterexercise2;public class tenth {public static void main(String[] args) {// TODO Auto-generated method stubfinal double RADIANS=Math.PI/180.0;int angle=0;System.out.println("angle\tsine\tcosine");for(int i=0;i<=36;i++){System.out.println(angle+"\t"+Math.sin(angle*RADIANS)+"\t"+Math.cos(angle*RADIANS)); angle += 10;}}}//exercise 5-21package fivechapterexercise3;import java.util.Scanner;//not precisepublic class first {public static void main(String[] args) {// TODO Auto-generated method stubScanner in=new Scanner(System.in);System.out.print("Enter ten numbers:");double []number=new double[10];for(int i=0;i<10;i++){number[i]=in.nextDouble();}System.out.println("The mean is "+average(number));System.out.println("The standard deviation is "+standarddeviation(number)); }public static double average(double ...average){double sum=0;for(int i=0;i<average.length;i++){sum=sum+average[i];}return sum/average.length;}public static double standarddeviation(double ...number){double sum=0;double squaresum=0;for(int i=0;i<number.length;i++){squaresum += Math.sqrt(number[i]);sum += number[i];}double num1=squaresum-Math.sqrt(sum)/(number.length);double num2=num1/(number.length-1);double calculation=Math.pow(num2,0.5);return calculation;}}//exercise 5-22package fivechapterexercise3;public class second {public static void main(String[] args){System.out.println("sqrt of 4 is "+sqrt(4));}public static double sqrt(double number){double lastguess=1;double reduce=1;while (reduce>0.00000001){double nextguess=(lastguess+(number/lastguess))/2;reduce=nextguess-lastguess;lastguess=nextguess;}return lastguess;}}//exercise 5.23package fivechapterexercise3;import chenqingyuan.RandomCharacter;public class third {public static void main(String[] args) {// TODO Auto-generated method stubfor(int i=0;i<100;i++){if(i%10==0)System.out.println();System.out.print(RandomCharacter.getRandomUpperCaseLetter()+" "); }System.out.println("\n\n");for(int i=0;i<100;i++){if(i%10==0)System.out.println();System.out.print(RandomCharacter.getRandomDigitCharacter()+" ");}}}//exercise 5.26package fivechapterexercise3;import chenqingyuan.math;public class sixth {public static void main(String[] args) {// TODO Auto-generated method stubint count=0;int integer=1;while(count<100){if(math.isPrime(integer)&&math.isPalindrome(integer)){if(count%10==0)System.out.println();System.out.print(integer+" ");count++;}integer++;}}}//exercise 5-27package fivechapterexercise3;import chenqingyuan.math;public class seventh {public static void main(String[] args) {// TODO Auto-generated method stubint count=0;int integer=1;while(count<100){if(math.isPrime(integer)&&math.isPrime(math.reverse(integer))&&!math.isPalindrome(integer)){if(count%10==0)System.out.println();System.out.print(integer+" ");count++;}integer++;}}}package fivechapterexercise3;public class eifhth {public static void main(String[] args) {// TODO Auto-generated method stubSystem.out.println("p\t\t2^p-1");for(int p=1;p<=31;p++){int number=(int)Math.pow(2,p)-1;if(chenqingyuan.math.isPrime(number))System.out.println(p+"\t\t"+number);}}}//exercise 5.29package fivechapterexercise3;public class ninth {public static void main(String[] args) {// TODO Auto-generated method stubint num1=(int)(Math.random()*6)+1;int num2=(int)(Math.random()*6)+1;int sum=num1+num2;System.out.print("You rolled "+num1+" + "+num2+" = "+sum);System.out.println();if(sum==3||sum==12){System.out.println("You lose");System.exit(0);}else if(sum==7||sum==11){System.out.println("You win");System.exit(0);}else{while(true){int num3=(int)(Math.random()*6)+1;int num4=(int)(Math.random()*6)+1;int add=num3+num4;if(sum==add){System.out.println("point is "+sum);System.out.print("You rolled "+num3+" + "+num4+" = "+add);System.out.println();System.out.println("You win");System.exit(0);}else if (add==7){System.out.println("point is "+sum);System.out.print("You rolled "+num3+" + "+num4+" = "+add); System.out.println();System.out.println("You lose");System.exit(0);}}}}}//exercise 5.30package fivechapterexercise3;import chenqingyuan.math;public class tenth {public static void main(String[] args) {// TODO Auto-generated method stubfor(int i=1;i<1000;i++){if(math.isPrime(i)&&math.isPrime(i+2))System.out.println("("+i+","+(i+2)+")");}}}//exercise 5.32package fivechapterexercise4;public class second {public static void main(String[] args) {// TODO Auto-generated method stubint count=0;for(int i=1;i<=10000;i++){int num1=(int)(Math.random()*6)+1;int num2=(int)(Math.random()*6)+1;int sum=num1+num2;if(sum==3||sum==12){continue;}else if(sum==7||sum==11){count++;continue;}else{while(true){int num3=(int)(Math.random()*6)+1;int num4=(int)(Math.random()*6)+1;int add=num3+num4;if(sum==add){count++;break;}else if (add==7){break;}}}}System.out.println("The number if times you win is "+count);}}//exercise 5.33package fivechapterexercise4;import chenqingyuan.math;//System.currentTimeMillis() display is USA timepublic class third {public static void main(String[] args) {// TODO Auto-generated method stublong millisecond=System.currentTimeMillis();long second=millisecond/1000%60;long minute=millisecond/1000/60%60;//+8 is to solve the time differencelong hour=(millisecond/3600/1000+8)%24;long day=(millisecond/3600/1000+8)/24;//judge yearlong daya=day-730;long day1=daya%1461;long count=daya/1461;//judge yearlong years=1970+2+4*count;if(day1>366){years =years+1;day1 -= 366;}while(day1>365){years +=1;day1 -= 365;}//resolve error !!To solve the time differenceday1 +=1;//judge monthint month=1;int mark;while(true){if(month==1||month==3||month==5||month==7||month==8||month==10||month==12){mark=(int)day1/32;if(mark!=0){day1 -= 31;month++;}elsebreak;}else if(month==2){int numberofmonth=0;if(!math.isLeapYear((int)years))numberofmonth=28;elsenumberofmonth=29;mark=(int)day1/(numberofmonth+1);if(mark!=0){day1 -= numberofmonth;month++;}elsebreak;}else {mark=(int)day1/31;if(mark!=0){day1 -= 30;month++;}elsebreak;}}System.out.println("Current date and time is "+math.getMonthName(month)+" "+day1+","+years+" "+hour+":"+minute+":"+second); }}//exercise 5.35package fivechapterexercise4;import java.util.Scanner;public class fifth {public static void main(String[] args) {// TODO Auto-generated method stubScanner in=new Scanner(System.in);System.out.print("please input side:");int side=in.nextInt();System.out.println("This area is "+area(side));}public static double area(int side){double molecular=5*side*side;double denominator=4*Math.tan(Math.PI/5);return molecular/denominator;}}//exercise 5.36package fivechapterexercise4;import java.util.Scanner;public class sixth {public static void main(String[] args) {// TODO Auto-generated method stubScanner in=new Scanner(System.in);System.out.print("input number of side and side:");int numberofside=in.nextInt();int side=in.nextInt();System.out.println("This area is "+area(numberofside,side)); }public static double area(int n,int side){double molecular=n*side*side;double denominator=4*Math.tan(Math.PI/n);return molecular/denominator;}}。
