C# 0 The Complete Reference

a

, was indeed modified by 

Sqr( )

:

a before call: 10

a after call: 100

Using

ref

, it is now possible to write a method that exchanges the values of its two 

value-type arguments. For example, here is a program that contains a method called 

Swap( )

 that exchanges the values of the two integer arguments with which it is called:

// Swap two values.

using System;

class ValueSwap {

  // This method now changes its arguments.

  public void Swap(ref int a, ref int b) {

    int t;

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    t = a;

    a = b;

    b = t;

  }

}

class ValueSwapDemo {

  static void Main() {

    ValueSwap ob = new ValueSwap();

    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);

  }

}

The output from this program is shown here:

x and y before call: 10 20

x and y after call: 20 10

Here is one important point to understand about