【原】输入角度，求三角函数

#include <stdio.h>

#include <math.h>

#define PI 3.141592

double x,y;

void main()

{

printf("请输入度数:");

scanf("%lf",&x);

y=x/180*PI;

printf("正弦: %lf\n余弦: %lf\n正切: %lf\n", sin(y), cos(y), tan(y));

}

/*

double sin(double y)

{

sin(y);

return sin(y);

}

double cos(double y)

{

cos(y);

return cos(y);

}

double tan(double y)

{

tan(y);

return tan(y);

}

*/