Ref vs Val

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

/*
Value1: 1
Pass By Value: 5
Value1: 1

-------

Value2: 1
Pass By Ref: 5
Value2: 5

-------

Ref1: 1
Pass By Value: 5
Ref1: 5

-------

Ref2: 1
Pass By Ref: 10
Ref2: 10
*/



namespace RefVsVal
{
    class Program
    {
        static void Main(string[] args)
        {

            int v1 = 1;  //Value Type

            Console.WriteLine("Value1: {0}", v1);

            //Passing value by value
            ValByVal(v1);

            //Even though we've passed the value to a function and changed it, the value is unchanged.
            //This is because we created a copy!
            Console.WriteLine("Value1: {0}", v1);

            Console.WriteLine(); Console.WriteLine("-------"); Console.WriteLine();

            int v2 = 1;  //Value Type

            Console.WriteLine("Value2: {0}", v2);

            //Passing value by referance
            ValByRef(ref v2);

            //This time we pass by value, so the change occurs here too!
            Console.WriteLine("Value2: {0}", v2);

            Console.WriteLine(); Console.WriteLine("-------"); Console.WriteLine();

            int[] r1 = new[] { 1 };  //Referance Type

            Console.WriteLine("Ref1: {0}", r1[0]);

            //passing referance by value
            RefByVal(r1);

            //We changed a value inside the array,
            //but not change the referance [to a new array]
            Console.WriteLine("Ref1: {0}", r1[0]);

            Console.WriteLine(); Console.WriteLine("-------"); Console.WriteLine();

            int[] r2 = new[] { 1 };  //Referance Type

            Console.WriteLine("Ref2: {0}", r2[0]);

            //passing referance by referance
            RefByRef(ref r2);

            //We changed the referance - in this case by pointing it to a new array!
            Console.WriteLine("Ref2: {0}", r2[0]);

            Console.ReadLine();

        }

        static void ValByVal(int i)
        {
            i = 5;
            Console.WriteLine("Pass By Value: {0}", i);
        }

        static void ValByRef(ref int i)
        {
            i = 5;
            Console.WriteLine("Pass By Ref: {0}", i);
        }

        static void RefByVal(int[] a)
        {
            a[0] = 5;
            Console.WriteLine("Pass By Value: {0}", a[0]);
            a = new[] { 10 };
        }

        static void RefByRef(ref int[] a)
        {
            a = new[] { 10 };
            Console.WriteLine("Pass By Ref: {0}", a[0]);
        }
    }
}