include

double countpi(double eps) /eps为允许误差/
{
int m=1;
double temp=1.0,s=0;
while(temp>=eps)
{ s+=temp;
temp=tempm/(2m+1);
m++;
}
return(2s);
}
main()
{FILE fp;
double eps=1e-5,pi;
if((fp=fopen(“p7_3.out”,”w”))==NULL)

{ printf(“cannot open the file\n”);
exit(0);

}
pi= countpi(eps);
printf(“pi=%lf\n”,pi);
fprintf(fp,”pi=%lf\n”,pi);
fclose(fp);
}