C plus plus Constructor
In C plus plus, constructor is a special method which is invoked automatically at the time of object creation. It is used to initialize the data members of new object generally. The constructor in C plus plus has the same name as class or structure.
There can be two types of constructors in C plus plus.
- Default constructor
- Parameterized constructor
C plus plus Default Constructor
A constructor which has no argument is known as default constructor. It is invoked at the time of creating object.
Let’s see the simple example of C plus plus default Constructor.
- #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 plus plus Parameterized Constructor
A constructor which has parameters is called parameterized constructor. It is used to provide different values to distinct objects.
Let’s see the simple example of C plus plus 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(101, "Abhishek", 890000); //creating an object of Employee Employee e2=Employee(102, "Mukul", 59000); e1.display(); e2.display(); return 0; }
Output:
101 Abhishek 890000 102 Mukul 59000