public static void Swap(ref int x,ref int y)
Console.WriteLine("In Swap method: "+
public static void Main()
Console.Write("Nhap so nguyen a: ");
a = int.Parse(Console.ReadLine());
Console.Write("Nhap so nguyen b: ");
b = int.Parse(Console.ReadLine());
Console.WriteLine("\nBefore swapping: "+
Console.WriteLine("After swapping: "+