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Constructors in C#

C#.Net Constructors: Learn, what is the constructor, how they declared, defined and their properties with an example in C#.Net?

Constructors are special type of methods in C#, which is automatically invoked when an object is being created. It is basically used to:

1. To initialize data member of class.
2. To allocate memory for data member.

There are following properties of constructor in C#:

1. Constructor has the same name as the class name. It is case sensitive.
2. Constructor does not have return type.
3. We can overload constructor, it means we can create more than one constructor of class.
4. We can use default argument in constructor.
5. It must be public type.

Consider the program:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class EMP
    {
        private string name ;
        private int age     ;
        private int salary  ;

		//constructor
        public EMP()
        {
            name   = "Herry";
            age    = 20     ;
            salary = 23000  ;
        }
        public void setEmp(string name, int a = 18, int salary = 20000) 
        {
            this.name   = name      ;
            this.age    = a       ;
            this.salary = salary    ;


        }

        public void printEmp()
        {
            Console.WriteLine("\nEmployee Record: ");
            Console.WriteLine("\tName  : " + name   );
            Console.WriteLine("\tAge   : " + age    );
            Console.WriteLine("\tSalary: " + salary );

        }
		
    }

    class Program
    {
        static void Main()
        {
            EMP E0 = new EMP();

            E0.printEmp();

            EMP E1 = new EMP();

            E1.setEmp("Sandy", salary: 48500);
            E1.printEmp();

            EMP E2 = new EMP();

            E2.setEmp("Mark", a:33);
            E2.printEmp();
        }
    }
}

Output

Employee Record:
        Name  : Herry
        Age   : 20
        Salary: 23000

Employee Record:
        Name  : Sandy
        Age   : 18
        Salary: 48500

Employee Record:
        Name  : Mark
        Age   : 33
        Salary: 20000

In above example EMP () method is constructor, it initializes object, when object creates.

Normally Constructors are following type:

1. Default Constructor or Zero argument constructor
2. Parameterized constructor
3. Copy constructor