使用 std::random_device 可以设置一系列浮点数但不包括某些数字吗？

Question

As mentioned in the title I want to generate a random floating-point number between -10 and 10 but I want to make it so that it can't generate a number between -1.99 and 1.99.

My code for randomly generating numbers:

std::random_device random;
std::mt19937 gen(random());
std::uniform_real_distribution<float> dis(-10.0f, 10.0f);

for (int n = 0; n < 10; ++n)
{
    std::cout << dis(gen); << std::endl;
}

Answer 1

you can use std::piecewise_constant_distribution :

#include <iostream>
#include <random>
 
int main() {
  std::random_device rd;
  std::mt19937 gen(rd());
  // 50% of the time, generate a random number between -10.0f and -1.99f
  // 50% of the time, generate a random number between  1.99f and  10.0f
  std::vector<float> i{-10.0f,  -1.99f, 1.99, 10.0f};
  std::vector<float> w{1,  0,  1};
  std::piecewise_constant_distribution<float> dis(i.begin(), i.end(), w.begin());
  for (int n = 0; n < 10; ++n)
    std::cout << dis(gen) << std::endl;
}

Demo.