如何手动生成随机数

import random

random_number = random.randint(1, 100)
print(random_number)

var random_number = Math.floor(Math.random() * 100) + 1;
console.log(random_number);

import java.util.Random;

public class RandomNumberGenerator {
    public static void main(String[] args) {
        Random random = new Random();
        int random_number = random.nextInt(100) + 1;
        System.out.println(random_number);
    }
}

using System;

class RandomNumberGenerator {
    static void Main() {
        Random random = new Random();
        int random_number = random.Next(1, 101);
        Console.WriteLine(random_number);
    }
}

<?php
$random_number = rand(1, 100);
echo $random_number;
?>