How can a totally logical machine like a computer generate a random number?

Have you wondered how a random number is generated in programming languages on a totally logical device like a Computer?
Recently I read an article about it which throws a light on this interesting topic.


Here is the link:
http://computer.howstuffworks.com/question697.htm

Phone Numbers Comparison in Different Country Formats

In every country phone numbers are represented in its own format. For example : In some country a phone number could be in (914) 575-4231 format whereas in another country the same number could be in 914-575-42131 format. So if we want to compare two numbers represented in different format, we could do this by removing their formatting and compare their actual value.

using System;

using System.Collections;

class Program

{

    static void Main()

    {

        string num1 = "800-555-1212"; // Format -1

        string num2 = "(800) 555 1212"; // Format -2

        if (FetchDigitsOnlyFromPhoneNumber(num1) ==

        FetchDigitsOnlyFromPhoneNumber(num2))

        {

            Console.WriteLine("Number in both the formats are Equal !");

        }

        else

        {

            Console.WriteLine("Unequal Numbers !");

        }

        Console.Read();

    }

    private static string FetchDigitsOnlyFromPhoneNumber(string formattedNumber)

    {

        string actualNumber;

        actualNumber = formattedNumber;

        actualNumber = actualNumber.Replace("(", string.Empty);

        actualNumber = actualNumber.Replace(")", string.Empty);

        actualNumber = actualNumber.Replace("+", string.Empty);

        actualNumber = actualNumber.Replace("-", string.Empty);

        actualNumber = actualNumber.Replace(" ", string.Empty); //Blank

        actualNumber = actualNumber.Replace(".", string.Empty);

        return actualNumber;

    }

}

One liner Factorial calculating program using recursion in C#

using System;

public class Program

{

    //Using recursion

    static long Factorial(long number)

    {

        return ((number <= 1) ? 1 : number * Factorial(number - 1));

    }

    static void Main(string[] args)

    {

        long numToFindFact = 6;

        Console.WriteLine("The factorial of " + numToFindFact  + " is: {0}\n", Factorial(numToFindFact));

    }

}