c语言计算 sinx 怎么实现

!1111111111111111111111111111111111111111111111111111

#include
#define EPS 1e-7
int main()
{
double x, res = 0, sing;
char flag = 1;
int itr = 1;
std::cin >> x;
res += (sing = x);
while(sing > EPS)
{
flag = -flag;
itr += 2;
sing = sing * x * x / (itr - 1) / itr;
res += flag * sing;
}
std::cout << res;
return 0;
}

这个流程图已经写的十分详细了,你是哪部分的写法不理解呢