在C ++中生成随机数的最好方法是什么？ [英] What is the best way to generate random numbers in C++?

问题描述

生成随机数的最佳方法是什么？

解决方案

>

您没有C ++ 11支持，甚至没有TR1（因此您没有其他选择）

然后，您可以考虑使用以下C风格的解决方案，（为了这个社区的声誉，请参阅 rand（）Considered有害）以透明字体写成：

这里是简单的C风格函数，它从 min 到 max （包括）的间隔生成随机数。这些数字似乎非常接近均匀分布。

  int irand（int min，int max）{
 return（（double）rand（）/（（double）RAND_MAX + 1.0））*（max  -  min + 1）+ min; 
} 
  

，不要忘记呼叫 srand 之前使用它：

  int occurences [8] = {0} ; 
 
 srand（time（0））; 
 for（int i = 0; i <100000; ++ i）
 ++出现[irand（1,7）]; 
 
 for（int i = 1; i <= 7; ++ i）
 printf（％d，occurences [i]）; 
  

输出： 14253 14481 14210 14029 14289 14503 14235





另请参阅：

在范围内生成一个随机数？

在整个范围内生成随机数字

，并找到一些时间，并至少观察前11分钟的上述 ：//en.cppreference.com/w/cpp/numeric/randomrel =nofollow> < random> 已通过 Kerrek SB 。

What is the best way to generate random numbers?

解决方案

If and only if:

• you are not looking for "perfect uniformity" or

• you have no C++11 support and not even TR1 (thus you don't have another choice)

then you might consider using the following C-style solution, which (for the sake of the reputation of this community ~ see rand() Considered Harmful) is written in strike-through font:

Here's the simple C-style function that generates random number from the interval from min to max, inclusive. Those numbers seem to be very close to being uniformly distributed.

int irand(int min, int max) {
    return ((double)rand() / ((double)RAND_MAX + 1.0)) * (max - min + 1) + min;
}

and don't forget to call srand before you use it:

int occurences[8] = {0};

srand(time(0));
for (int i = 0; i < 100000; ++i)
    ++occurences[irand(1,7)];

for (int i = 1; i <= 7; ++i)
    printf("%d ", occurences[i]);

output: 14253 14481 14210 14029 14289 14503 14235

Also have a look at:
Generate a random number within range?
Generate random numbers uniformly over an entire range
and find some time and watch at least first 11 minutes of aforementioned video

Otherwise:

use <random> just like it was pointed out by Kerrek SB already.

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