源程序：
#include <iostream>
#include <string>
#include <cstdlib>
using namespace std;
class point
{
private:
double x, y;
public:
point() {};
point(double a, double b) :x(a), y(b) {};
friend ostream & operator<<(ostream &os,const point &c); //友元，流插入
friend istream & operator>>(istream &is,point &c); //友元，流提取
};
ostream &operator<<(ostream &os, const point &c)
{
//if (c.y >= 0)
// os << c.x << "," << c.y << endl;
//else
// os << c.x << "," << (-c.y) << endl;
os << sqrt(c.x*c.x + c.y*c.y);
return os;
}
istream &operator>>(istream & is, point &c)
{
is >> c.x >> c.y;
return is;
}
int main()
{
point c, c1;
int n;
//cout << "输入两个坐标点和一个整数，以空格分隔" << endl;
cout << "输入第一个坐标点：";
cin >> c;
cout << "输入第二个坐标点：";
cin >> c1;
cout << "输入一个整数：";
cin >> n;
//cin >> c >> c1 >> n;
cout << "第一个坐标点到原点的距离：" << c << endl << "整数为："<<n << endl<< "第二个坐标点到原点的距离：" <<c1<<endl;
system("pause");
return 1;
}
运行结果：
