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();
     cout << i++ << endl;
     cout << ++i << endl;
     cout << i-- << endl;
     cout << --i << endl;
     cout << *i << endl;
     return ;
 }

Output:

[5]

[7]

[7]

[5]

5