operator ++

The difference lies in what signature you choose for your overload(s) of operator ++.

Cited from the relevant article on this subject in the C++ FAQ (go there for more details):

class Number {
  public:
    Number& operator++ ();     // prefix ++: no parameter, returns a reference
    Number  operator++ (int);  // postfix ++: dummy parameter, returns a value
};

Object non-member function:

This is another way to do this: As long as the functions are in the same namespace as the object they are referring too, they will be considered when the compiler will search for a fonction to handle ++t ;or t++ ; code:

class T
{
    // etc.
} ;


T & operator++(T & p_oRight) // ++A
{
   // Do increment of p_oRight value
   return p_oRight ;
}

T operator++(T & p_oRight, int) // A++
{
   T oCopy ;
   // Copy p_oRight into oCopy
   // Do increment of p_oRight value
   return oCopy ;
}

The difference lies in what signature you choose for your overload(s) of operator ++.

Cited from the relevant article on this subject in the C++ FAQ (go there for more details):

class Number {
  public:
    Number& operator++ ();     // prefix ++: no parameter, returns a reference
    Number  operator++ (int);  // postfix ++: dummy parameter, returns a value
};