!
#include <stdio.h>
#include <math.h>
double fun ( double eps)
{int n;
double i,j=1;
for(n=0,i=0;j>=eps;n++)
{i=i+j;
double j=n/(2n+1)*j;
}
}
main( )
{ double x;void NONO ();
printf("Input eps:") ;
scanf("%lf",&x); printf("\neps = %lf, PI=%lf\n", x, fun(x));
NONO();
}
void NONO ()
{/* 本函数用于打开文件,输入数据,调用函数,输出数据,关闭文件。 */
FILE *fp, *wf ;
int i ;
double x ;
fp = fopen("in.dat","r") ;
wf = fopen("out.dat","w") ;
for(i = 0 ; i < 10 ; i++) {
fscanf(fp, "%lf", &x) ;
fprintf(wf, "%lf\n", fun(x)) ;
}
fclose(fp) ;
fclose(wf) ;
}
![图片说明](https://img-ask.csdn.net/upload/201912/08/1575801647_206417.png)