'this' pointer in C++

• The this pointer is an implicit parameter to all member functions.

• this pointer represents the current or invoking object of class.

• this pointer is not accessible in static member function.

• Friend functions do not have this pointer, because friends are not members of class.

• Only member functions/non-static function have this pointer.

Following are the situations where ‘this’ pointer is used:

1. When local variable’s name is same as member’s name
   Example:

   #include<iostream>
   using namespace std;
   /* local variable is same as 
   a member's name */
   class Test
   {
   private:
    int x;
   public:
    void setX (int x)
     {
   /* The 'this' pointer is used to 
     retrieve the object's x hidden
      by the local variable 'x'
    */
       this->x = x;
     }
    void show()
     {
      cout<<"x = " << x << endl; 
     }
   };
    
   int main()
   {
      Test obj;
      int x = 20;
      obj.setX(x);
      obj.show();
      return 0;
   }                    

   OUTPUT:

   x = 20

2. To return reference to the calling object.
   

   /* Reference to the calling
    object can be returned */
   Test& Test::func ()
   {
      // Some processing
      return *this;
   }                  

Next topic is File handling