More C# Examples / Practice Programs

What is the difference between Public, Private, Protected and Internal?

What is the difference between Public, Private, Protected and Internal?: There are five types of access specifiers in c# public, private, protected, internal and protected internal. In this article, I have explained each access specifier with an example.

1) Public

– No restrictions to access.

– The type or member can be accessed by any other code in the same assembly or another assembly that references it.

– Most common access specifier in C#.

using System;
namespace AccessModifiers
{
    class Program
    {
        class sample
        {
            public int num1;
        }
        static void Main(string[] args)
        {
            sample obj = new sample();


            obj.num1 = 10;

            Console.WriteLine("Value of number 1 : {0}", obj.num1);
            Console.ReadLine();
        }
    }
}

From above example you can see num1 can directly accessible by sample object.

2) Private

– The type or member can be accessed only by code in the same class or struct.

– Access is limited to within the class definition and any class that inherits from the class.

using System;
namespace AccessModifiers
{
    class Program
    {
        class sample
        {
            public int num1;
            int num2;
        }
        static void Main(string[] args)
        {
            sample obj = new sample();
            obj.num1 = 100;
             //As num2 is a private variable, It is not accesible by object of sample class
            Console.WriteLine("Value of number 1 : {0}", obj.num1);
            Console.ReadLine();
        }
    }
}

As num2 is a private variable, It is not accessible by object of sample class

3) Protected

– The type or member can be accessed only by code in the same class or struct, or in a class that is derived from that class.

using System;

namespace Protected_Access_Specifier
{
    class BaseClass
    {
       protected int num1;
        protected int num2;
    }

    class Sample : BaseClass
    {
        static void Main()
        {
            Sample obj1 = new Sample();
            // Direct access to protected members:      
            obj1.num1 = 5;
            obj1.num2 = 10;

            Console.WriteLine("Num1 = {0}, Num2 = {1}", obj1.num1, obj1.num2);
        }
    }
}

If we define variable as a private variable then compile time error will occur.

4) Internal

– The type or member can be accessed by any code in the same assembly, but not from another assembly.

– It is the default access specifiers for a class in C# programming.

using System; 
namespace Internal_Access_Specifier
{
    class Sample
    {
        internal string companyname; // String Variable declared as internal
        public void print()
        {
            Console.WriteLine("\nCompany name is " + companyname);
        }
    } 
    class Program
    {
        static void Main(string[] args)
        {
            Sample obj1 = new Sample();
            Console.Write("Your Company name is :");
            // Accepting value in internal variable
            obj1.companyname = Console.ReadLine();
            obj1.print();
            Console.ReadLine();
        }
    }
}

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