【水文】计算sin x的值

#include <stdio.h>

int main(){

int n, sign;

double x, res;

res = 0;

sign = 1;

scanf("%d %lf", &n, &x);

for (int i = 1; i <= n; i++)

{

res += (double)sign * pow(x, 2 * i - 1) / factorial(2 * i - 1);

sign = -sign; // 实现变号

}

printf("%.4f\n", res);

printf("%.4f\n", sin(x));

return 0;

}