Wednesday 25 February 2015

Operator Overloading in C++ : PART 1 (++ Operator)



 I am now teaching under graduate students C++ programming. I thought I will share the programs I have prepared so that it benefits everyone.

Overloading ++ Operator

In this post I have added sample programs overloading the ++ Operator. In C++ we have preincrement and postincrement operators. For example ++a is preincrement whereas a++ is postincrement. So in order to handle these two situations there should be two versions of the operator++( ) function. The two versions are shown below. 

    void operator++(int y);  // for postincrement
   // The call a++; will invoke this version
   // The call a++; is same as the call a.operator++();
   
   void operator++( );        // for preincrement
   // The call ++a; will invoke this version
   // The call ++a; is same as the call a.operator++(0);


Click here to download the C++ program. 


Overloading ++ Operator with Friend Function
In C++ we can overload the ++ operator by using friend function.  Here also we need two versions to manage the preincrement and postincrement versions of the ++ operator. The two versions are given below.

   void operator++(A, int);  // for postincrement
   // The name of the Class is A
   // The call a++; will invoke this version
   // The call a++; is same as the call operator++(a);
   
   void operator++(A);        // for preincrement
   //The name of the class is A 
   // The call ++a; will invoke this version
   // The call ++a; is same as the call operator++(a,0);

Click here to download the C++ program. 


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