在 Java 中如何在特定范围内生成随机整数？

Question

How do I generate a random int value in a specific range?

I have tried the following, but those do not work:

Attempt 1:

randomNum = minimum + (int)(Math.random() * maximum);
// Bug: `randomNum` can be bigger than `maximum`.

Attempt 2:

Random rn = new Random();
int n = maximum - minimum + 1;
int i = rn.nextInt() % n;
randomNum =  minimum + i;
// Bug: `randomNum` can be smaller than `minimum`.

转载于:https://stackoverflow.com/questions/363681/how-to-generate-random-integers-within-a-specific-range-in-java

Answer 1

Use:

minimum + rn.nextInt(maxValue - minvalue + 1)