Two different random number generators giving the same answer?

Question

 static void Main(string[] args) { //random number gen Console.WriteLine("Array Random Number:"); randomGenA(); Console.WriteLine("------------------"); //LIST: random movie picker... Console.WriteLine("List Random Number:"); randomGenB(); Console.WriteLine("------------------"); Console.ReadLine(); } static void randomGenA() { Random randomA = new Random(); int randomNumA = randomA.Next(51); Console.WriteLine(randomNumA); } static void randomGenB() { Random randomB = new Random(); int randomNumB = randomB.Next(0,51); Console.WriteLine(randomNum); } }

I wanted them both to produce two different random numbers but instead I keep getting the same random number from both of them. Why does it do this?

The time difference between the instantiations of these two Random objects is minimal, causing them to have the same seed. Introduce a delay (please don't) or share the Random instance. — Jeroen Vannevel
– Jeroen Vannevel, Commented Sep 2, 2015 at 20:28
add System.Threading.Thread.Sleep(50); between your method call — Abin
– Abin, Commented Sep 2, 2015 at 20:32
create one Random randomB = new Random(); in class and use it in both methods. — M.kazem Akhgary
– M.kazem Akhgary, Commented Sep 2, 2015 at 20:32

lintmouse · Accepted Answer · 2015-09-02 20:45:53Z

Declare a class level random and use it in your methods:

private static Random _random = new Random();

Your methods would look like:

static void randomGenA() { int randomNumA = _random.Next(51); Console.WriteLine(randomNumA); } static void randomGenB() { int randomNumB = _random.Next(0,51); Console.WriteLine(randomNum); }

Check this out for further reading: http://www.dotnetperls.com/random

Tripp Kinetics · Accepted Answer · 2015-09-02 20:28:42Z

As per the documentation:

https://msdn.microsoft.com/en-us/library/system.random%28v=vs.110%29.aspx

Two Randoms with the same seed will provide the same sequence of numbers. Simply don't use the same seed. If you don't specify a seed, it uses the system time. Wait some time between the two instantiations and it will use two different system times.

Collectives™ on Stack Overflow

Two different random number generators giving the same answer?

2 Answers 2

Comments

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Linked

Related