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C++ Tutorial - Function members in classes:

   Functions declared inside a class can be any of the following four types. This C++ Tutorial explains each one of them as below.

Ordinary member functions :

   These are ordinary functions defined with a return type and parameters. The return type can also be void. The special trait about member functions is they can access the private/protected data members of their class and manipulate them. No external functions can access the private/protected data members of a class. The sample below this C++ Tutorial uses an ordinary member function Add(), returning an integer valueConstructors in C++ are special member functions of a class. They have the same name as the Class Name. There can be any number of overloaded constructors inside a class, provided they have a different set of parameters. There are someimportant qualities for a constructor to be noted.Destructors in C++ also have the same name, except for the fact that they are preceded by a '~' operator. The destructors are called when the object of a class goes out of scope. It is not necessary to declare a constructor or a destructor inside a class. If not declared, the compiler will automatically create a default one for each. If the constructor/destructor is declared as private, then the class cannot be instantiated. Check below for the sample class of the C++ tutorial for an example of destructor..

Constructors:

   

• Constructors have the same name as the class.
• Constructors do not return any values
• Constructors are invoked first when a class is initialized. Any initializations for the class members, memory allocations are done at the constructor.

   In the example class given below in this C++ tutorial has the constructor Example_Class(), with the same name as the class.

Destructors:

   

C++ Tutorial - Access Level:

   The classes in C++ have 3 important access levels. They are Private, Public and Protected. The explanations are as follows.

Private:

   The members are accessible only by the member functions or friend functions.

Protected:

   These members are accessible by the member functions of the class and the classes which are derived from this class.

Public:

   Accessible by any external member. Look at the sample class below.

C++ Tutorial - Example of a class:

   class Example_class //Sample Class for the C++ Tutorial
   {
       private:
         int x; //Data member
         int y; // Data member
       public:
         Example_Class() //Constructor for the C++ tutorial
         {
             x = 0;
             y = 0;
         }
       ~Example_Class() //destructor for the C++ Tutorial
       { }
      int Add()
      {
         return x+y;
      }
};