实验五实验报告

实验五

姓名游小锋班级单周上课的那班学号 11231193 实验一

一：根据泰勒多项式求sinx，cosx的近似值（-∞

运行源程序：

#include

#include

#include

void main()

{

FILE *fp;

if((fp=fopen("Taylor's formula.txt","w"))==NULL)

{

printf("File open error! \n");

exit(0);

}

int i;

float c,d,x,p,y;

x=0;

while(x<=90)

{i=1;p=1;

c=p;

y=x*3.14/180;

while(i<=6)

{p=-p*(y*y)/((2*i-1)*(2*i));

c=c+p;i++;}

fprintf(fp,"cos %.0f=%.5f",x,c);

fprintf(fp," ");

d=sqrt(1-c*c);

fprintf(fp,"sin %.0f=%.5f\n",x,d);

x=x+5;

}

fclose(fp);

}

运行结果见Taylor’s formula.txt

实验二：

实验题目：从文件中读入n个正整数，求他们的最大公约数和最小公倍数，写回到原文件。

实验源程序：#include

#include

GCD(int x,int y);

void main()

{

FILE *fp; int x,y,n,gcd,lcm,i,gcd2;

char d;

fp=fopen("e:\\yxf.txt","r");

if(fp==NULL)

{

printf("文件打不开！\n"); exit(0) ;

}

n=0;

d=fgetc(fp);

while(d!=' '){

n=n*10+d-'0'; d=fgetc(fp);

printf("read n！\n");

}

x=0;

d=fgetc(fp);

while(d!=' '){

x=x*10+d-'0'; d=fgetc(fp); printf("read x！\n");

}

y=0;

d=fgetc(fp);

while(d!=' ')

{

y=y*10+d-'0'; d=fgetc(fp);

printf("read y！\n");}

gcd=GCD( x, y);

lcm=x*y/gcd;

i=3;

printf("n=%d！\n",n);

while(i<=n)

{

x=0;

d=fgetc(fp);

while(d!=' '){ x=x*10+d-'0'; d=fgetc(fp);} gcd=GCD(gcd,x);

gcd2=GCD(lcm,x);

lcm=x*lcm/gcd2;

i++;

}

fclose(fp);

printf("GCD=%d\tLCM=%d\n",gcd,lcm);

fp=fopen("e:\\yxf.txt","a");

if(fp==NULL)

{ printf("文件打不开！\n"); exit(0) ;}

fprintf(fp,"\n%d",gcd); fprintf(fp,"\n%d",lcm); fclose(fp);

}

GCD(int x,int y)

{

int r;

r=x%y;

while(r)

{x=y;y=r;r=x%y;}

return y;

}

实验结果：

实验三

实验题目：用记事本输入一段英文。写一程序，从文件中读出这段文章，在显示器上输出。

运行源程序:

#include

#include

void main( )

{

char c;FILE *fp;

if(( fp=fopen("news.txt","r"))==NULL)

{

printf("Can't open this file!\n");

exit(0);

}

while((c=fgetc(fp))!=EOF)

printf("%c",c);

printf("\n");

fclose(fp);

}

运行结果:

#include

#include

GCD(int x,int y);

void main()

{

FILE *fp; int x,y,n,gcd,lcm,i,gcd2; fp=fopen("e:\\yxf.txt","r");

if(fp==NULL)

{

printf("文件打不开！\n");

exit(0) ;

}

fscanf(fp,"%d",n);

printf("read n！\n");

//fscanf(fp,"%d%d",&x,&y); fscanf(fp,"%d",x);

printf("read x！\n");

fscanf(fp,"%d",y);

printf("read y！\n");

gcd=GCD( x, y);

lcm=x*y/gcd;

i=3;

printf("n=%d！\n",n);

while(i<=n)

{

// fscanf(fp,"%d",&x);

fscanf(fp,"%d",x);

gcd=GCD(gcd,x);

gcd2=GCD(lcm,x);

lcm=x*lcm/gcd2;

i++;

}

fclose(fp);

printf("GCD=%d\tLCM=%d\n",gcd,lcm);

fp=fopen("e:\\yxf.txt","a");

if(fp==NULL)

{ printf("文件打不开！\n"); exit(0) ;} fprintf(fp,"\n%d",gcd);

fprintf(fp,"\n%d",lcm);

fclose(fp);

}

GCD(int x,int y)

{

int r;

r=x%y;

while(r)

{x=y;y=r;r=x%y;}

return y;

}