Java生成3个随机数

Question

如何给我的math.random一个参数，使我总是至少接收，但不超过3位？我目前正在社区学院上我的第一节编程课，这是一个用Java编写的小型彩票项目的作业。任何帮助或更深入的解释将是非常感谢的。谢谢!

//randomly generate 3 digit lottery number
    int lottery = (int)(Math.random() * 1000);

    System.out.println(lottery);

    int lotteryDigit1 = lottery / 100;
    int lotteryDigit2 = lottery / 10 % 10;
    int lotteryDigit3 = lottery % 10;

    System.out.println(lotteryDigit1 + " digit 1 ");
    System.out.println(lotteryDigit2 + " digit 2 ");
    System.out.println(lotteryDigit3 + " digit 3 ");

为了澄清我写这个程序的依据，下面是一个类似的程序，它为彩票生成"2“随机数。我的工作是修改它来创建3个随机数。

public static void main(String[] args) 
{

    //generate lottery number
    int lottery = (int)(Math.random() * 100);

    //prompt the user to enter a guess
    Scanner input = new Scanner (System.in);
    System.out.println("Enter your lottery pick (two digits): ");
    int guess = input.nextInt();

    //get digits from lottery
    int lotteryDigit1 = lottery / 10;
    int lotteryDigit2 = lottery % 10;

    //get digits from guess
    int guessDigit1 = guess / 10;
    int guessDigit2 = guess % 10;

    System.out.println("The lottery number is " + lottery);

    //check the guess
    if (guess == lottery)
        System.out.println("Exact match: you win $10,000");
    else if (guessDigit2 == lotteryDigit1 && guessDigit2 == lotteryDigit2)
            System.out.println("Match all digits: you win $3,000");
    else if (guessDigit1 == lotteryDigit1
            || guessDigit1 == lotteryDigit2
            || guessDigit2 == lotteryDigit1
            ||guessDigit2 == lotteryDigit2)
        System.out.println("Match one digit: you win $1,000");
    else
        System.out.println("Sorry, no match");






}

}

Answer 1

使用：

int lottery = 100 + (int) (Math.random()*899);

用这一行来生成至少三位数的数字，我不知道你为什么要用彩票作为所有其他随机数的基础？如果你除以100，那么肯定得到的数字将小于3位数，模10将给我0-9，而不是3位数！

Answer 2

您可以为随机数编写一个具有最小和最大界的方法。这两个界限都包括在内：

private void run() {
    int min = 100;
    int max = 999;
    int result = random(min, max);
    System.out.println(result);
}

private int random(int min, int max) {
    Random random = new Random();
    return min + random.nextInt(max - min + 1);
}