C ++随机数从1到非常大的数（例如2500万） [英] C++ Random number from 1 to a very large number (e.g. 25 million)

问题描述

我已经考虑过使用 rand（） 但我是正确的，认为最大数量， RAND_MAX is = 32000（有关于）？

有没有办法解决这个问题，一种方法不会降低选择非常低的数字的概率，也不会增加挑选高/中等数字的概率？

编辑：@Jamey D的方法完全独立于Qt。

解决方案

新的C ++ 11 std :: uniform_real_distribution

  #include< ; random> 
 
 std :: random_device rd; 
 std :: mt19937 gen（rd（））; 
 
 std :: uniform_real_distribution<>分布（1，25000000）; 
 
 //生成一个随机整数：
 double random = distribution（gen）; 
  

How would you make a function that generates a random number from 1 to 25 million?

I've thought about using rand() but am I right in thinking that the maximum number, RAND_MAX is = 32000 (there about)?

Is there a way around this, a way that doesn't reduce the probability of picking very low numbers and doesn't increase the probability of picking high / medium numbers?

Edit: @Jamey D 's method worked perfectly independent of Qt.

解决方案

You could (should) use the new C++11 std::uniform_real_distribution

#include <random>

std::random_device rd;
std::mt19937 gen(rd());

std::uniform_real_distribution<> distribution(1, 25000000);

//generating a random integer:
double random = distribution(gen);

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