c语言题利用公式s=1/12-1/22+1/32-1/42

Question

利用公式s=1/12-1/22+1/32-1/42……计算直到最后一项的绝对值小于0.000001的s的值

Answer 1

double s = 0;
int sign = 1;
int div = 12;
do
{
double d = sign / (double)div;
s += d;
sign = -sign;
div += 10;
} while (fabs(d) >= 0.00001);
printf("%lf", s);