C语言计算三角函数

#define _CRT_SECURE_NO_WARNINGS 1

#include
#include
#define pi 3.1415926535897932384626433832795028841971

int main() {

	int a;
	double b;

	printf("选择函数(1.sin 2.cos 3.tan)：");
	scanf("%d", &a);
	printf("输入待计算角度值：");
	scanf("%lf", &b);
	switch (a) {
	case 1:printf("nsin(%.0lf°) = %.3lfn", b, sin(b*pi / 180)); break;
	case 2:printf("ncos(%.0lf°) = %.3lfn", b, cos(b*pi / 180)); break;
	case 3:printf("ntan(%.0lf°) = %.3lfn", b, tan(b*pi / 180)); break;
	default:printf("输入的三角函数有误n");
	}

	return 0;
}