如何使用rand函数生成特定范围内的数字? [英] How to use the rand function to make numbers in a specific range?

问题描述

我想在特定范围内生成随机数，例如在 18 到 35 之间选择一个随机数"?我怎样才能用 rand() 函数做到这一点?

I would like to make random numbers in a specific range, like "pick a random number between 18 and 35"? How can I do that with the rand() function?

推荐答案

如果这是用 C 编写的，那么您就非常接近了.编译此代码:

If this is written in C, then you are pretty close. Compiling this code:

#include <stdio.h>
#include <stdlib.h>

int main() {
    int i;
    for (i = 0; i < 1000000; i++) {
        printf("%d
", rand()%(35-18+1)+18);
    }
}

并在管道中运行它会产生以下输出:

And running it in a pipeline produces this output:

chris@zack:~$ gcc -o test test.c
chris@zack:~$ ./test | sort | uniq -c
  55470 18
  55334 19
  55663 20
  55463 21
  55818 22
  55564 23
  55322 24
  55886 25
  55947 26
  55554 27
  55342 28
  55526 29
  55719 30
  55435 31
  55669 32
  55818 33
  55205 34
  55265 35

关键是你忘了加 1 -- 围栏错误.

The key is you forgot to add 1 -- the fencepost error.

您可以将其概括为一个函数:

You can generalize this into a function:

int random_between(int min, int max) {
    return rand() % (max - min + 1) + min;
}

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