Operator Overloading in C++ : PART 2 ([ ] Operator)

  Array subscript operator [ ] used for array indexing can also be overloaded in C++. In this post I have added a program in which the array subscript operator [ ] is overloaded. The program illustrates an overloaded array subscript operator.

The program also offers a solution to the C++ puzzle question given below.

Floating Point Number in Array Subscript

Write a C++ program in which the following statement compiles without an error.

cout << a[0.123];

The difficulty in solving this puzzle arises from the fact that array subscript should be an integer.  

If you pass a float value to a normal array subscript you will get the following error "Invalid type for array subscript". 

One possible solution is to overload the array subscript operator.

Click here to download the C++ program solving the puzzle.

There might be some other solutions to this puzzle. If you know any other solution please share them here. 

   

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.