Swaping two number using third variable by making object

using System;
class Mark
{
int a,b,temp;     \\ taking three variable.
public void Swapnum()      \\ here i take input on this function
{
Console.WriteLine("Enter your 1st number");
a=Convert.ToInt32(Console.ReadLine());
Console.WriteLine("Enter your 2st number");
b=Convert.ToInt32(Console.ReadLine());
}
public void Swapsum()
{
temp=a;        \\ stroing value of 'a' on temp
a=b;               \\stroing value of 'b' on 'a'
b=temp;          \\stroing value of 'temp' on 'b'
}
public void Display()
{
Console.WriteLine("your swap number is --: {0}",a);
Console.WriteLine("your swap number is --: {0}",b);
}
public static void Main()
{
Mark av=new Mark();
av.Swapnum();
av.Swapsum();
av.Display();
}
}