Scope resolution operator vs this pointer

this pointer in C++

The this pointer in C++ is used to access the object variables in a function when we have the local variables with the same name. Local variables have precedence over object variables, so when we access a variable by name local variable is accessed. So, to access the object variables, we have to use this pointer. this pointer is used to point to the current object used to invoke the function.

The syntax to use this pointer in c++ is as follows:

this -> variable_name

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Following is an example of how we can use this pointer in C++ to access the object members in C++.

#include<iostream>
using namespace std;

class Demo{
    int var;
   
    public:
    //Constructor that sets the value of var for each object.
    Demo(int x){
        var = x;
    }

    //A function that prints the value of var
    void demo_func(int var){
        cout<<this->var<<endl;  //By using this->variable_name we can access the object variable
        cout<<var;  //This will print the local variable
    }
};


//Driver function
int main(){

    Demo obj(100);
    obj.demo_func(10);

    return 0;
}

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Output

100
10

Scope Resolution Operator vs this pointer

The scope resolution operator(::) in C++ is used to access the class members or static members of a class when we have a local variable present with the same name. 

In contrast, this pointer in C++ is used to access the object variable when a local variable with the same name is present in a function.

FAQs

1. What is the purpose of using a scope resolution operator in C++?
   The purpose of using a scope resolution operator in C++ is to access the class members or static variables in C++.
    
2. What is the symbol of the scope resolution operator in C++?
   The symbol for scope resolution operator in C++ is two colon symbols(::).
    
3. What are static members in C++?
   Static members are also called class members because they are the property of a class and not an object. They are shared among all the objects of a class.
    
4. What are formal and actual parameters in C++?
   Formal parameters are the local variables that are declared in function declarations, and actual parameters are the variables that are passed as an argument to a function at the function call.
    
5. What is the purpose of this pointer in C++?
   The “this” pointer points to the invoking object, and so it is used to denote the current object that is used to invoke the function.

Key Takeaways

In this article, We discussed the scope resolution operator vs this pointer in C++. We discussed how the scope resolution operator is different from the “this” point.

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