在C ++中生成一个统一的随机整数 [英] Generating a uniform random integer in C++

问题描述

问题是我需要生成一个0到999之间的随机整数(用于研究数学猜想).所有这些值都必须具有相同的上升概率.

The problem is that I need to generate a random integer between 0 and 999 (for investigation of a mathematical conjecture). All of the values need to have the same probability of coming up.

我尝试了rand()，但是RAND_MAX为32767(在我的编译器上)，这意味着仅采用rand() % 1000会导致出现第一个1–767的可能性大大提高(并且假设所有可能性首先在rand()中具有相同的概率.

I have tried rand(), but with RAND_MAX being 32767 (on my compiler) this means that just taking rand() % 1000 leads to the first 1–767 being significantly more likely to come up (and that's assuming that all possibilities have the same probability in rand() in the first place).

我使用的是Windows，所以/dev/random不能选择.

I'm using Windows so /dev/random isn't an option.

推荐答案

您可以使用 uniform_int_distribution 与C ++ 11:

You can do something like this using uniform_int_distribution with C++11:

#include <iostream>
#include <random>

int main()
{
    std::random_device rd;
    std::mt19937 gen(rd());
    std::uniform_int_distribution<> dis(0, 999);

    for (int n=0; n<1000; ++n)
        std::cout << dis(gen) << ' ';
    std::cout << '\n';
}

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