pi的近似值

#include<stdio.h>
#include<math.h>
int main(){
int sign=1;
double pi=0.0,n=1.0,term=1.0;
while(fabs(term)>=1e-6){
    pi=pi+term;
    n+=2;
    sign=-sign;
    term=sign/n;
}
pi*=4;
printf("%10.8f",pi);
}