Function Overloading In C++

• Function overloading is the process of defining functions that two or more functions can have the same name, but with different parameters.
• The secret to overloading is that each redefinition of the function must use,
  1. Different types of arguments
  2. Different number of parameters

Different types of arguments

     void display(int a);
     void display(float b);
     void display(char c);

Finding the best match

• The actual arguments are comparing with the formal arguments (This process is called argument matching or process of disambiguation).
• The compiler finds the best match through the following steps:
  1. Search for an exact match
  2. A match through the promotion
  3. A match through standard conversion rules
  4. A match through the user-defined conversion

Search for an exact match

• If the type of actual and formal argument is exactly the same, the compiler invokes that function.

     void display(int a); //function1
     void display(float b); //function2
     void display(char c); //function3
     .....
     display(2);

     it invoke the function function 1

A match through the promotion

• If an exact match is not found, an attempt is made for finding an exact match through promotion.

     void display(int a); //function 1
     void display(int b); //function 2
     void display(char c); //function 3
     ......
     display(2.3);

     matches the function 1 through promotion.

A match through standard conversion rules

• If the above two steps fail, an attempt is made to achieve a match through a standard conversion of the actual argument.

     void display(char c);//function 1
     void display(float b);//function 2
     display(214);//It will matches the function 2 and int 214 will converted into float.

A match through the user-defined conversion

• If the above all steps fail the compiler will try the user-defined conversion to find a unique match.