简单的系统函数应用举例

#include<iostream>
#include<iomanip> 
#include<cmath> 
using namespace std;

const double PI = 3.1415926;
/*系统函数应用举例*/
int main()
{
double angle; /*定义一个角度变量*/
cout<<"请输入角度值:";
cin>> angle;
double radian = angle * PI /180; /*转化为弧度值*/ 
cout << "sin("<<angle<<")="<<sin(radian)<<endl;
cout << "cos("<<angle<<")="<<cos(radian)<<endl;
cout << "tan("<<angle<<")="<<tan(radian)<<endl;
return 0;
}