operator.cpp

#include <iostream>
#include <vector>
using namespace std;

class test
{
  public:
    int v;
    /*构造函数*/
    test() : v(0) {}
    test(const int &a) : v(a) {}
    test(const test &t1) : v(t1.v) {}

    /*以下重载小于号 < */
    //比较两个对象的大小
    bool operator<(const test &t1) const
    {
        return (v < t1.v);
    }
    //比较对象和int的大小
    bool operator<(const int &t1) const
    {
        return (v < t1);
    }
    //友元函数，比较int和对象的大小
    friend inline bool operator<(const int &a, const test &t1)
    {
        return (a < t1.v);
    }

    /*以下重载赋值号 = */
    //对象间赋值
    test &operator=(const test &t1)
    {
        v = t1.v;
        return *this;
    }
    //int赋值给对象
    test &operator=(const int &t1)
    {
        v = t1;
        return *this;
    }

    /*以下重载加号 + */
    //对象加上 int
    test operator+(const int &a)
    {
        test t1;
        t1.v = v + a;
        return t1;
    }
    //对象加对象
    test operator+(test &t1)
    {
        test t2;
        t2.v = v + t1.v;
        return t2;
    }

    /*以下重载加等号 += */
    //对象加上对象
    test &operator+=(const test &t1)
    {
        v += t1.v;
        return *this;
    }
    //对象加上int
    test &operator+=(const int &a)
    {
        v += a;
        return *this;
    }

    /*以下重载双等号 == */
    //对象==对象
    bool operator==(const test &t1) const
    {
        return (v == t1.v);
    }
    //对象==int
    bool operator==(const int &t1) const
    {
        return (v == t1);
    }

    /*以下重载 输入>> 输出<< */
    /*友元函数，输出对象*/
    friend inline ostream &operator<<(ostream &os, test &t1)
    {
        cout << "class t(" << t1.v << ")" << endl;
        return os;
    }
    /*友元函数，输入对象*/
    friend inline istream &operator>>(istream &is, test &t1)
    {
        cin >> t1.v;
        return is;
    }
};

int main()
{
    test t0, t1(3);
    test t2(t1);
    cout << t0 << t1 << t2;
    cin >> t1;
    t2 = t1;
    t2 += t1;
    t1 += 10;
    cout << t2;
    if (t1 < t2)
        cout << "t1 < t2";
    else if (t1 == t2)
        cout << "t1 = t2";
    else /* t1 > t2*/
        cout << "t1 > t2";
    cout << endl;
    system("pause");
    return 0;
}