RandRange(0, 5) returns only 1. Why?

Development Programming & Scripting
1

I don’t know what am I doing wrong here. The comment says:

@anonymous_user_b2e972a1 A random number >= Min and <= Max

FRandomStream test;
auto random = test.RandRange(1, 5);	
UE_LOG(LogTemp, Warning, TEXT("%d"), random);

The console will only output this:

LogTemp:Warning: 1
2

Hey Klawd3-

Rather than using FRandomStream to get a random number you can use FMath::FRandRange(A, B);. This will return a random number in the range of A through B-1 (so using (1, 6) will return a number in the range of 1-5)).

Cheers

3

Hi ,
I had already resorted to use FMath library, and it’s working fine.
Could you tell me if UE libraries contain a Fisher-Yates algorithm implementation for true rng? Or do I have to implement one myself?

Thanks.

4

It appears that rand() is calling the STL version rather than its own implementation. If you want something along the lines of the Fisher-Yates algorithm you will have to implement it on your end.

5

Hi , it’s still not clear to me if I should, or not, use std:: library functions. I indirectly learned to only use what UE offers, on the c++ side. If I can infact use them without causing any compatibility/packaging problems, the standard library does infact have a native fisher-yates implementation for rng.