this Pointer

this Pointer

• Definition : The this pointer is an implicit pointer available inside all non‒static member functions.

• It stores the address of the object for which the member function is currently being executed.

• The keyword this identifies a special type of pointer. Suppose that you create an object named x of class A and class A has a nonstatic member function f(). If you call the function x.f(), the keyword this in the body of f() stores the address of x. You cannot declare this pointer or make assignments to it.

• A static member function does not have a this pointer.

• The this pointer is passed as a hidden parameter to the member function call and it is available in the function definition as a local variable. Below is an example in which this pointer is used to refer the num variable.

C++ Program

#include<iostream>

using namespace std;

class test

{

private:

    int num;

public:

void get_val(int num)

{

   //this pointer retreives the value of obj.num

   //this pointer is hidden by automatic variable num

   this‒>num=num;

}

void print_val()

{

   cout<<"\n The value is "<<num;

}

};

int main()

{

   test obj;

   int num;

   cout<<"\n Enter Some Value";

   cin>>num;

   obj.get_val(num);

   obj.print _val();

   return 0;

}

Output

Enter Some Value 10

The value is 10

• The this pointer points to the object for which the member function is called. Hence from above code obj.get_val(num) can be interpreted as get_val(&obj,num); That means this pointer is passed as a hidden argument to the called function by some automatic variable like num.

Review Question

1. What is the use of this pointer?