java - 创建随机值的最佳方法是什么？

Question

我正在尝试为我的游戏创建随机值以在屏幕上显示敌人。但有时会显示 2 有时会显示 3 ...我想问哪个是创建随机值的最佳公式..这是我迄今为止的随机值

 random = 1 * (int) (Math.random() * 100);

Answer 1

“但是有时会显示 2，有时会显示 3”

给定完全随机的数字...在从 0 到 99 的每 100 个随机值中，您会发现平均有 1.0 个 double 。每 10,000 个值平均会出现一次三元组。给定 1000 万个随机数，java.util.Random 在我的机器上产生以下结果:

Doubles: 99873Triples: 985Double Rate: 1 in 100Triple Rate: 1 in 10152

Source code:

import static java.lang.System.*;

import java.util.Random;

public class Sandbox {
    public static final int NUM_ITERATIONS = 10000000;
    public static void main(String[] args) {
        Random rand = new Random();

        int cur;
        int last = -1;
        int secondLast = -2;
        int nDoubles = 0;
        int nTriples = 0;

        for (int i = 0; i < NUM_ITERATIONS; i++) {
            cur = rand.nextInt(100);
            if (cur == last) {
                nDoubles++;
                if (cur == secondLast) nTriples++;
            }
            secondLast = last;
            last = cur;
        }

        out.println("Doubles: " + nDoubles);
        out.println("Triples: " + nTriples);
        out.println();
        out.println("Double Rate: 1 in " + Math.round(1.0 * NUM_ITERATIONS / nDoubles));
        out.println("Triple Rate: 1 in " + Math.round(1.0 * NUM_ITERATIONS / nTriples));

        exit(0);
    }
}