In the C#, Everything is associated with classes and objects which is dependent on basic concepts of Object-Oriented Programming.
C# is an object-oriented language, program is designed using objects and classes in C# programming language.
C# Object
In C#, Object is a real-world entity, for example, real, dog, car, pen, mobile, laptop etc.
In other words, object is the new instance of class or an entity that has a state and behavior. All the member's values are accessed through object.
Let's see in the given below example to create object using new keyword.
Employee objEnployee= new Employee ();//creating an object of Employee
In this example, Employee is the type and objEmployee is the reference variable that refers to the instance of Employee class. The new keyword allocates memory at runtime.
C# Class
In C#, class is a collection of properties or group of similar objects.
To create a class, use the class keyword like as given below.
public class Employee
{
public int ID;//field or data member
public string FullName;//field or data member
}
C# Class and Object Example
An object is created from a class. I have already create the class named Employee, so now you can use this to create objects.
To create an object of Employee, specify the class name, followed by the object name, and use the keyword new:
using System;
public class Employee
{
public int ID;//data member (also instance variable)
public string FullName;//data member(also instance variable)
public static void Main(string[] args)
{
Employee objEmployee= new Employee();//creating an object of Employee
objEmployee.ID= 1002;
objEmployee.FullName= "Sylvia Neupane";
Console.WriteLine(objEmployee.ID);
Console.WriteLine(objEmployee.FullName);
}
}
Output
1002
Sylvia Neupane
Multiple Objects
using System;
public class Employee
{
public int ID;//data member (also instance variable)
public string FullName;//data member(also instance variable)
public static void Main(string[] args)
{
Employee objEmployee1= new Employee();//creating an object of Employee: first object
Employee objEmployee2= new Employee();//creating an object of Employee: second object
objEmployee1.ID= 1002;
objEmployee1.FullName= "Sylvia Neupane";
Console.WriteLine(objEmployee1.ID);
Console.WriteLine(objEmployee1.FullName);
objEmployee2.ID= 1003;
objEmployee2.FullName= "Rabina Neupane";
Console.WriteLine(objEmployee2.ID);
Console.WriteLine(objEmployee2.FullName);
}
}
Output
1002
Sylvia Neupane
1003
Rabina Neupane
Another C# Class Example: Having Main() in another class
using System; public class Employee
{ public int ID;
public strinig FullName;
}
public class EmployeeInfo{
public static void Main(string[] args)
{
Employee objEmployee= new Employee();
objEmployee.ID= 1002;
objEmployee.FullName= "Sylvia Neupane";
Console.WriteLine(objEmployee.ID);
Console.WriteLine(objEmployee.FullName);
}
}
Output
1002
Sylvia Neupane
C# Class : Initialize and Display data through method
using System;
public class Employee
{
public int ID;
public string FullName;
public void insert(int i, String n)
{
Id= i;
FullName= n;
}
public void display()
{
Console.WriteLine(ID+ " " + FullName);
}
}
public class EmployeeInfo{
public static void Main(string[] args)
{
Employee objEmployee= new Employee ();
Empoyee objeEmployee2= new Employee();
objEmployee.insert(1002, "Sylvia Neupane");
objEmployee2.insert(1003, "Rahul Neupane");
objEmployee.display();
objEmployee2.display();
}
}
Output
1002 Sylvia Neupane
1003 Rahul Neupane
C# Class : Store and Display Employee Information
using System;
public class Employee
{
public int id;
public String name;
public float salary;
public void insert(int i, String n,float s) {
id = i;
name = n;
salary = s;
}
public void display()
{
Console.WriteLine(id + " " + name+" "+salary);
} } public class EmployeeInfo{
public static void Main(string[] args)
{
Employee objEmployee= new Employee();
Employee objEmployee2= new Employee();
objEmployee.insert(1002, "Sylvia",450000f);
objEmployee2.insert(1003, "Rahul", 510000f);
objEmployee.display();
objEmployee2.display();
}
}
Output
1002 Sylvia 450000
1003 Rahul 510000