新手C++求助,此程序有点错误求,高手帮忙改下或者帮忙写个，小弟在这感激不尽啊...

#include<iostream>
#include<cmath>
using namespace std;
class TwoCoor
{
private:
    double x,y;
public:
    TwoCoor(double X=0,double Y=0):x(X),y(Y) {};
    friend TwoCoor operator+(TwoCoor p1,TwoCoor p2);
    friend TwoCoor operator-(TwoCoor p1,TwoCoor p2);
    friend       double  dist(TwoCoor p1,TwoCoor p2);
    friend TwoCoor &operator<<(ostream &os,TwoCoor &t);
    friend TwoCoor &operator>>(istream &is,TwoCoor &t);
};
TwoCoor operator+(TwoCoor p1,TwoCoor p2)
{
    return TwoCoor(p1.x+p2.x,p1.y+p2.y);
}
TwoCoor operator-(TwoCoor p1,TwoCoor p2)
{
    return TwoCoor(p1.x-p2.x,p1.y-p2.y);
}
double  dist(TwoCoor p1,TwoCoor p2)
{
    double x=(p1.x-p2.x);
    double y=(p1.y-p1.y);
    return sqrt(x*x+y*y);
}
TwoCoor &operator<<(ostream &os,TwoCoor &t)
{
    os<<"\t"<<t.x<<"\t";
    os<<t.y<<endl;
    return t;
}
TwoCoor &operator>>(istream &is,TwoCoor &t)
{
    cout<<"坐标点的横坐标:";
    is>>t.x;
    cout<<"坐标点的纵坐标:";
    is>>t.y;
    return t;
}
int main()
{
    TwoCoor t1,t2;
    char select;
    while(1)
    {
        cout<<"------------------坐标点计算系统-----------------------"<<endl;
        cout<<"         0            计算两坐标点对应坐标之和         "<<endl;
        cout<<"         1            计算两坐标点对应坐标之差         "<<endl;
        cout<<"         2            计算两坐标点的距离               "<<endl;
        cout<<"         3            退出系统                         "<<endl;
        cout<<"*******************************************************"<<endl;
        cout<<"请输入你的选择:";
        cin>>select;
        if(select=='0')
        {
            cout<<"请输入坐标点1的坐标:"<<endl;
            cin>>t1;
            cout<<"---------------------------------------"<<endl;
            cout<<"\t"<<"横坐标"<<"\t"<<"纵坐标"<<endl;
            cout<<"点1";
            cout<<t1;
            cout<<"---------------------------------------"<<endl;
            cout<<"请输入坐标点2的坐标:"<<endl;
            cin>>t2;
            cout<<"---------------------------------------"<<endl;
            cout<<"\t"<<"横坐标"<<"\t"<<"纵坐标"<<endl;
            cout<<"点2";
            cout<<t2;
            cout<<"---------------------------------------"<<endl;
            cout<<"\t"<<"\t"<<"\t"<<"\t"<<"横坐标"<<"\t"<<"纵坐标"<<endl;
            cout<<"两坐标点的对应坐标相加为:"<<operator+(t1,t2);
        }
        else if(select=='1')
        {
            cout<<"请输入坐标点1的坐标:"<<endl;
            cin>>t1;
            cout<<"---------------------------------------"<<endl;
            cout<<"\t"<<"横坐标"<<"\t"<<"纵坐标"<<endl;
            cout<<"点1";
            cout<<t1;
            cout<<"---------------------------------------"<<endl;
            cout<<"请输入坐标点2的坐标:"<<endl;
            cin>>t2;
            cout<<"---------------------------------------"<<endl;
            cout<<"\t"<<"横坐标"<<"\t"<<"纵坐标"<<endl;
            cout<<"点2";
            cout<<t2;
            cout<<"---------------------------------------"<<endl;
            cout<<"\t"<<"\t"<<"\t"<<"\t"<<"横坐标"<<"\t"<<"纵坐标"<<endl;
            cout<<"两坐标点的对应坐标相减为:"<<operator-(t1,t2);
        }
        else if(select=='2')
        {
            cout<<"请输入坐标点1的坐标:"<<endl;
            cin>>t1;
            cout<<"---------------------------------------"<<endl;
            cout<<"\t"<<"横坐标"<<"\t"<<"纵坐标"<<endl;
            cout<<"点1";
            cout<<t1;
            cout<<"---------------------------------------"<<endl;
            cout<<"请输入坐标点2的坐标:"<<endl;
            cin>>t2;
            cout<<"---------------------------------------"<<endl;
            cout<<"\t"<<"横坐标"<<"\t"<<"纵坐标"<<endl;
            cout<<"点2";
            cout<<t2;
            cout<<"---------------------------------------"<<endl;
            cout<<"两坐标点的距离为:"<<dist(t1,t2)<<endl;
        }
        else if(select=='3')
            exit(0);
        else
        {
            cout<<"输入错误，请重新输入"<<endl;
            continue;
        }

    }
}