Efficiently generating random bytes of data in C++11/14

Question

My requirement is to generate random bytes of data (not random numbers) aka uniformly distributed bits.

As such I was wondering what are the correct/efficient w

Answer 1

I think the key to efficiency is to get the maximum number of values from every random number that is generated. Here's a small tweak to your original code that does that.

#include 
#include 
#include 

int main()
{
   std::random_device rd;
   std::uniform_int_distribution dist(0,0xFFFFFFFFu);
   std::vector data(1000);
   int offset = 0;
   uint32_t bits = 0;
   for (char& d : data)
   {
      if (offset == 0)
         bits = dist(rd);
      d = static_cast(bits & 0xFF);
      bits >>= 8;
      if (++offset >= 4)
         offset = 0;
   }
   return 0;
}

If getting 4 bytes from every 32 bits doesn't work, try 3 bytes from 24 bits.