c++ atna2 特殊值处理

atan2是求解反正切角度的函数，返回值为 (-Pi, Pi]

#include <iostream>

int main()
{
	float y1 = -0.000000;
	float x1= -0.000000;
	float y2 = 0.000000;
	float x2 = -0.000000;

	float deg1 = atan2(y1, x1);
	float deg2 = atan2(y2, x2);

	printf("deg1: %f and deg2: %f
", deg1, deg2);

	getchar();
	return 0;
}

当x值为0，y值为-0.000000/0.000000时候，返回值需要注意

deg1: -3.141593 and deg2: 3.141593