#include <bits/stdc++.h>
using namespace std;
double x,y;
double r,theta;
void calc(int i);
int main(int argc, const char * argv[]) {
    int code;
    while(1)
    {
        cout<<"(0为退出程序，1为平面直角化极坐标，2为极坐标化平面直角)"<<endl;
        cout<<"请输入值:";
        cin>>code;
        if(!code) break;
        calc(code);
    }
    return 0;
}
void calc(int i)
{
    if(i==1)
    {
        cout<<"请输入平面直角坐标系的x轴与y轴:";
        cin>>x>>y;
        r=sqrt(pow(x,2)+pow(y,2));
        theta=atan(y/x);
        cout<<"r="<<r<<" ";
        cout<<"theta="<<theta<<endl;
    }else if(i==2)
    {
        cout<<"请输入极坐标系的r与theta:";
        cin>>r>>theta;
        x=r*cos(theta);
        y=r*sin(theta);
        cout<<"x="<<x<<" ";
        cout<<"y="<<y<<endl;
    }
}