using System;
class Swap {
// This method now changes its arguments.
public void swap(ref int a, ref int b) {
int t;
t = a;
a = b;
b = t;
}
}
class MainClass {
public static void Main() {
Swap ob = new Swap();
int x = 10, y = 20;
Console.WriteLine("x and y before call: " + x + " " + y);
ob.swap(ref x, ref y);
Console.WriteLine("x and y after call: " + x + " " + y);
}
}
x and y before call: 10 20
x and y after call: 20 10