NP138 Random

Thank you very much for explanation.

The r2.Next(150000) call produces a random integer 'i' in the range:

 0 <= i < 150000

so 75274 is within that range.

The r2.NextDouble() call produces a random double 'd' in the range:

0 <= d < 1

so 0.571986661558965 is within that range. 

Thank you for explanation.

How this can be explained?

Console.WriteLine(r2.Next(150000)); //75274

Console.WriteLine(r2.NextDouble()); //0.571986661558965

The number passed to the Random constructor is what's called a 'seed' value. This is simply a starting value from which the pseudo-random sequence of random numbers will be generated - it is nothing to do with the range of those numbers.

So, in the first example, calling Random.Next() without an argument can produce any random integer between 0 and int.MaxValue - 1 (2,147,483,646) inclusive. The number produced (214,873,035) is, of course, well within that range.

How can output of the following program be explained? Note that Random() constructor is holding a number 99830123.   

using System;

//using System.Collections.Generic;

//using System.Globalization;

//using System.IO;

//using System.Text;

public class MainClass

{

    public static void Main()

    {

        Random r2 = new Random(99830123);

        Console.WriteLine(r2.Next());     //214873035

        Console.WriteLine(r2.Next(150000));     //75274

        Console.WriteLine(r2.Next(9999, 100750));     //85587

        Console.WriteLine(r2.NextDouble());     //0.571986661558965

    }

}