C语言计算PI/2：莱布尼茨公式实现

#include <stdio.h>

int main() { double pi = 1; double numerator = 1, denominator = 3; int i;

for (i = 2; i <= 1000000; i++) {
    numerator *= (i - 1);
    denominator += 2;
    pi += (numerator / denominator);
}

pi *= 2;
printf('PI / 2 = %.15f\n', pi);

return 0;

}