圆周率计算--C语言实现

#include <stdio.h>
#include <math.h>
void main()
{
/*
int i,sum;
i = 1;
sum = 0;
for(;;)
{
sum = sum + i;   //0+1->sum
i++;
if(i>100) break;
}
printf("%d",sum);
getch();
*/
/*
int i,j;
for(j=1;j<11;j++)
printf("%4d",j);
printf("\n-----------------------------------------\n");

for(i=1;i<11;i++)
{
for(j=1;j<11;j++)
printf("%4d",i*j);
printf("\n");
}
*/
/*
int i;
for(i=100;i<200;i++)
{
if(i%3==0)
break;
printf("%5d",i);
}
*/
int s,i;
float deno,sign,pi,t;
sign = 1;
deno = 1;
pi = 1;
while(fabs(t)>=1e-7)
{
sign = -1*sign;
deno = deno+2;
t = sign/deno;
pi = pi+t;

}
printf("%6f   ",4*pi);

}