在awk中运行shell命令

计算sin(x) = x - x3/3! + x5/5! - x7/7! + ...直到最后一项的绝对值小于10-7为止。
#include <stdio.h>
#include <math.h>

#define EPS 1e-7
#define PI 3.14159

int main(void)
{
int n;
double x, an, sum;

printf("input x:");
scanf("lf", &x);
x = x * PI /180;
sum = 0;
an = x;
n = 1;
do
{
sum += an;
++ n;
an *= (-x * x) / ((2 * n - 2) * (2 * n - 1));
}while (fabs(an) >= EPS);
printf("sin(%.4f) = %.4f\n", x, sum);

return 0;
}