求π的近似值

#include <stdio.h>
#include <math.h>
int main()
{
    int sign,n;
    float p,i,t;
    i=1.0;
    sign=1;
    n=0;
    p=0.0;
    t=1.0;
    while(fabs(t)>=1e-6)
    {            
        sign=-sign;    
        i=i+2;
        p=p+t;
        t=sign/i;
        n=n+1;
    }
    p=p*4;
    printf("%f\n",p);//π的近似值
    printf("%d\n",n);//执行次数
    return 0;
}