Can no longer use experimental/random's randint()

[antisynth]

Hello! I am currently coding a little console game in C++, and in my game I have features that requires randint to be functional. For a long time, I was using #include <experimental/random> and it worked! Then, I decided to switch my IDE to Visual Studio Code, and suddenly experimental/random no longer existed and randint didn't work. The IDE I was using previously was Sublime Text. I tried to switch back to Sublime Text but it still wasn't working. How can I fix this problem? Is there a way I can download experimental/random and make it work again? Any help is appreciated! Thanks!

[helios]

Most likely you updated the compiler and the new version doesn't have <experimental/random> anymore. <experimental/*> headers are not meant to be used in productive code, they're meant as a demo of future capabilities. The implementation developers may remove such headers at any time.

Are you using threads? If not then just create a global generator and seed it when your program starts.

std::mt19937 rng;

int randint(int from, int to){
    return std::uniform_int_distribution<int>(from, to)(rng);
}

[mbozzi]

The lesson here is: never update development tools in the middle of a project.

[antisynth]

The issue is I don't even remember updating the compiler. It just stopped working the second I started coding in Visual Studio Code.

[helios]

Maybe Visual Studio Code updated it when you installed it.

[Thomas1965]

Does #include<random> work?

[deleted account xyzzy]

randint and the experimental header would be replaced with:

1. include <random> (and <chrono> if you want a C++ time seed)
2. instantiate a random number engine object
3. instantiate a distribution object, uniform_int_distribution would be a good fit.
4. generate your random number by calling the distribution object with the RNG as the input.

#include <iostream>
#include <chrono>
#include <random>

int main()
{
   // get a seed based on the system clock
   unsigned seed { static_cast<unsigned> (std::chrono::system_clock::now().time_since_epoch().count()) };

   // create a pseudo random number engine, seeding it with the time from earlier
   std::default_random_engine prng(seed);

   // create a distribution
   std::uniform_int_distribution<int> dist(1, 25);

   // let's generate some random numbers
   for (unsigned i { 1 }; i <= 25; i++)
   {
      std::cout << dist(prng) << ' ';

      if (!(i % 10))
      {
         std::cout << '\n';
      }
   }
   std::cout << '\n';
}

A bit complicated, but C++ random number generation has a wide variety of options when generating numbers, integral and real numbers.

If you don't need a lot of random numbers AND your compiler supports it you could use std::random_device:

#include <iostream>
#include <random>

int main()
{

   // create a true random number engine, no need to seed
   std::random_device prng;

   // create a distribution
   std::uniform_int_distribution<int> dist(1, 25);

   // let's generate some random numbers
   for (unsigned i { 1 }; i <= 25; i++)
   {
      std::cout << dist(prng) << ' ';

      if (!(i % 10))
      {
         std::cout << '\n';
      }
   }
   std::cout << '\n';
}

[antisynth]

Hey everyone! Thanks for all your replies. I found out how to implement random number generation into my game and make it work well. Thanks guys!

[deleted account xyzzy]

A paper on Random Number Generation in C++11 (and later)
http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2013/n3551.pdf

Has sample code for creating a random number toolkit. Drop it into a custom header file so you aren't trying to reinvent the wheel each time you need random numbers.