increment/decrement/dereference

 

#include <vector>
#include <deque>
#include <algorithm>
#include <iostream>
#include <ostream>
#include <iterator>
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);//随着class的不同,该行应该有不同的操作
        return *this;
    }

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

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

    //postfix: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;
    return 0;
}

Output:

[5]

[7]

[7]

[5]

5