What is Constructor In C++

Constructor in C++ is a specific method in C++ that is called automatically when an object is created. In general, it’s used to set up the data members of a new object. In C++, the constructor name is the same as a class or structure.

In C++, there are two types of constructors.

Default constructor
Parameterized constructor

C++ Default Constructor:

The default constructor is a function that has no argument. It is called at the time of Object creation.

Let’s look at a basic C++ default Constructor example.

#include <iostream>  
using namespace std;  
class Employee  
 {  
   public:  
        Employee()    
        {    
            cout<<"Default Constructor Invoked"<<endl;    
        }    
};  
int main(void)   
{  
    Employee e1; //creating an object of Employee   
    Employee e2;   
    return 0;  
}

Output:

Default Constructor Invoked
Default Constructor Invoked

C++ Parameterized Constructor:

A constructor is called a parameterized constructor which has parameters or arguments. It helps to provide different values according to different objects creation.

Let’s see an example of Parameterized constructor:

#include <iostream>
using namespace std;
class Employee {
   public:
       int id;//data member (also instance variable)    
       string name;//data member(also instance variable)
       float salary;
       Employee(int i, string n, float s)  
        {  
            id = i;  
            name = n;  
            salary = s;
        }  
       void display()  
        {  
            cout<<id<<"  "<<name<<"  "<<salary<<endl;  
        }  
};
int main(void) {
    Employee e1 =Employee(501, "Lingaraj", 750000); //creating an object of Employee 
    Employee e2=Employee(502, "Senapati", 80000); 
    e1.display();  
    e2.display();  
    return 0;
}

Output: