1). Swapping With Temporary variable

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;



namespace ConsoleApplication7

{

    

    class Program

    {

        static void Main(string[] args)

        {

            int A, B, temp;

            Console.Write("\nEnter the First Number(for A) : ");

            A = int.Parse(Console.ReadLine());

            Console.Write("\nEnter the Second Number(for B) : ");

            B = int.Parse(Console.ReadLine());

            temp = A;

            A = B;

            B = temp;

            Console.Write("\nAfter Swapping : ");

            Console.Write("\nFirst Number A is : " + A);

            Console.Write("\nSecond Number B is : " + B);

            Console.Read();

        }

    }

}

2). Without temp variable used in swapping 

1.  Use + and -
2. Use *and /

* and /

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication8
{
    class Program
    {
        public static void Main(string[] args)
        {
            int a = 15, b = 30;
            Console.WriteLine("Before swap a= " + a + " b= " + b);
            a = a * b; //a=450 (15*30)
            b = a / b; //b=15 (450/30)
            a = a / b; //a=30 (450/15)
            Console.Write("After swap a= " + a + " b= " + b);
            Console.WriteLine("\n");
        }
    }
}

+ and -

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;



namespace ConsoleApplication8

{

    class Program

    {

        public static void Main(string[] args)

        {

            int a = 30, b = 10;

            Console.WriteLine("Before swap a= " + a + " b= " + b);

            a = a + b; 

            b = a - b; 

            a = a - b; 

            Console.Write("After swap a= " + a + " b= " + b);

            Console.WriteLine("\n");

        }

    }

}