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pradeep 19Sep2012 19:13

Generating Random Numbers In Different Programming Languages
 
Random numbers or precisely in computer terms pseudo random number generators are extensively used in computing around the world today, which have great importance in the applications of gambling, statistics, computer simulation, cryptography, gaming, and areas where an arbitrary random value is required. A very simple example are the websites which send you a first time password when you sign up, these are random generated password.

Almost all the popular languages today have built-in PRNGs (Pseudo Random Number Generator), so let us look at how to generate random numbers in various popular languages.

Ruby



In Ruby we would be using the built-in function rand()

Code: Ruby

#!/usr/bin/ruby

print rand()
print "\n"
print rand(11)
print "\n"
print (rand() * 10000).to_i()


Output:
Code:

[pradeep@home-desktop test]# ruby test.rb
0.669492104182758
8
6275


Python



The random number generator function are found in the Python module random, you can load it as and when required.

Code: Python

#!/usr/bin/python

import random

print random.randint(0,9)
print random.random()


Output:
Code:

[pradeep@home-desktop test]# python test.py
4
0.339478502497


C#



In C# we need to use the Random class to generate random numbers, it's as easy as the following code looks.

Code: C#

Random random = new Random();

// now let's print a random number from 0 to 9
Console.WriteLine(random.Next(0, 9));


Java



The Java class Random in the java.util package, it pretty easy to use the class, see the following code example.

Code: Java

import java.util.Random;

Random generator = new Random();

int r1 = generator.nextInt();
double r2 = generator.nextDouble();


PHP



PHP has an in-built random number generator function rand(), it is automatically seeded when called the first time. Additionally you can install the mt_rand module which is based on Mersenne Twister algorithm which is faster and more reliable.

Code: PHP

print rand() . "\n";
print rand() . "\n";

print rand(4, 40). "\n";

// Generate better random numbers with mr_rand
print mt_rand() . "\n";
print mt_rand() . "\n";

print mt_rand(8, 80);


Perl



Perl's PRNG is similar to PHP's, except the function rand() does not accept range, instead it accepts an optional max value.

Code: Perl

print rand() . "\n";
print rand(10) . "\n"; # returns a number between 0 & 10


Erlang



Erlang provides uniform:random function to generate random numbers, and it works pretty much the same way as the functions we have reviewed so far in this article.

Code: Erlang

% generates a number between 0.0 to 1.1
random:uniform()
% generates a number between 0 to 10
random:uniform(10)


smp 22Sep2012 00:28

Re: Generating Random Numbers In Different Programming Languages
 
I would add the basic one. The one in C/C++ in GNU/Linux

main()
{
srand(time(NULL));
printf("%d",rand()%10); //prints a random number between 0 and 10(both exclusive)
}

Turbo/Borland C++

main()
{
randomize();
cout<<random(10);
}


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