How can I get a random number in Kotlin?

Question

A generic method that can return a random integer between 2 parameters like ruby does with rand(0..n).

Any suggestion?

Answer 1

Kotlin standard lib doesn't provide Random Number Generator API. If you aren't in a multiplatform project, it's better to use the platform api (all the others answers of the question talk about this solution).

But if you are in a multiplatform context, the best solution is to implement random by yourself in pure kotlin for share the same random number generator between platforms. It's more simple for dev and testing.

To answer to this problem in my personal project, i implement a pure Kotlin Linear Congruential Generator. LCG is the algorithm used by java.util.Random. Follow this link if you want to use it : https://gist.github.com/11e5ddb567786af0ed1ae4d7f57441d4

My implementation purpose nextInt(range: IntRange) for you ;).

Take care about my purpose, LCG is good for most of the use cases (simulation, games, etc...) but is not suitable for cryptographically usage because of the predictability of this method.