Randomizer.hpp

[Isamu]

What was the reason of removing Randomizer.hpp from the sfml package?

[FRex]

It was nearly completely useless and possibly harmful.
It consisted of few super short functions, had a global value, used srand and rand anyway and had idiotically non uniform distribution.
Use real randomness library, C++11 <random> header or write the entire 10 lines of 'wrapper' that 'Randomizer' used to be for C functions yourself.

[Sub]

Taken from stack overflow
--
#include <random>
#include <chrono>

unsigned seed = std::chrono::system_clock::now().time_since_epoch().count();
std::mt19937 rng(seed);
std::uniform_int_distribution<int> gen(min, max); // uniform, unbiased

int r = gen(rng);

[Jesper Juhl]

Just a few random  links that seem to be relevant here:

Pseudo-random number generation - http://en.cppreference.com/w/cpp/numeric/random

rand() Considered harmful - http://channel9.msdn.com/Events/GoingNative/2013/rand-Considered-Harmful

Probability and Games: Damage rolls - http://www.redblobgames.com/articles/probability/damage-rolls.html

Understanding randomness in terms of mastery - http://www.lostgarden.com/2012/12/understanding-randomness-in-terms-of.html

[SeriousITGuy]

Taken from stack overflow
--
#include <random>
#include <chrono>

unsigned seed = std::chrono::system_clock::now().time_since_epoch().count();
std::mt19937 rng(seed);
std::uniform_int_distribution<int> gen(min, max); // uniform, unbiased

int r = gen(rng);

I use this algorithm to generate random numbers, works like it should.
Made a few tests how good the distribution really is with 100 million numbers between 1 and 100. Good enough to (nearly) appear truly random.

Thanks Jesper for the additional links, some important and interesting info in there. 

[Nexus]

Thor also provides global random functions that use C++11 engines and uniform distributions. Global state is not always wanted, but sometimes you just need a random number without caring about where it comes from.

[paupav]

what's wrong with std::rand() ?

[Hapax]

what's wrong with std::rand() ?

rand() Considered harmful - http://channel9.msdn.com/Events/GoingNative/2013/rand-Considered-Harmful

std::rand() is okay if you need to populate some data for testing rather than just sequential numbering, but other than that, why not use the STL stuff?

[FRex]

• It's global state.
• There is no (sane) guarantee on max number returned, it's specified in a macro and it just has to be at least 32767 which is pretty low. I think it's that on VC++, on 32 bit GCC it's max int.
• There are no guarantees on quality, period or safety of numbers.
• Algorithm is anything implementers pick, state doesn't mandate that, it and it's properties can vary wildly across implementations.
• SFML used a very naive way of getting random float or int range from it.