increment/decrement/dereference操作符

 

#include <iostream>

using namespace std;

class INT
{
    friend ostream& operator<<(ostream& os, const INT& i);

public:
    INT(int i) : m_i(i) {};

    //prefix: increment and then fetch
    INT& operator++()
    {
        ++(this->m_i);
        return *this;
    }

    //fetch and then increment
    const INT operator++(int)
    {
        INT tmp = *this;
        ++(*this);
        return tmp;
    }

    //prefix:decrement and then fetch
    INT& operator--()
    {
        --(this->m_i);
        return *this;
    }

    //prefix : fetch and then decrement
    const INT operator--(int)
    {
        INT temp = *this;
        --(*this);
        return temp;
    }

    //dereference
    int& operator*() const
    {
        return (int&)m_i;
    }

private:
    int m_i;
};

ostream& operator<<(ostream& os, const INT& i)
{
    os << '[' << i.m_i << ']';
    return os;
}

int main()
{
    INT I(5);
    cout << I++ << endl;
    cout << ++I<<endl;
    cout << I--<<endl;
    cout << --I<<endl;
    cout << *I<<endl;

    getchar();
    return 0;
}

运行结果：