Java生成指定范围内的一个随机整数2种方式

	public static void main(String[] args) {
        for (int i = 1; i <= 80; i++) {
            int number = (int) (20 + Math.random() * (80 - 20 + 1));
            System.out.println(number);
        }
    }

Random random = new Random();
int num = random.nextInt(10); //这样写的话，生成[ 0，9]的随机整数数。

int num = random.nextInt(10+1);

Random random = new Random();
int num = min + random.nextInt( max - min + 1);

//生成【0，10】的随机整数
	Random random = new Random();
	int num = 0 + random.nextInt( 10 - 0 + 1);
//  int num = random.nextInt(11);

  public static void main(String[] args){
        System.out.println("==========Random对象调用方法产生随机数===========");
        int[] arr2 = new int[5];
        Random random = new Random();
        //产生【1-10】的随机数
        for (int i = 0; i < arr2.length; i++) {
            arr2[i] = random.nextInt(10 + 1);
            System.out.print(arr2[i] + "  ");
        }
  }

import java.util.Scanner;

public class Demo18 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int randomNumber = (int) (1 + Math.random() * (100 - 1 + 1));
        int userNumber;
        while (true) {
            System.out.println("请输入您猜测的数字[1，100]：");
            userNumber = sc.nextInt();
            if (userNumber == randomNumber) {
                System.out.println("恭喜您猜对了");
                System.out.println("系统生成的随机数：" + randomNumber);
                break;
            } else if (userNumber > randomNumber) {
                System.out.println("您猜的数字偏大");
            } else {
                System.out.println("您猜的数字偏小");
            }
        }
        System.out.println("游戏结束！");
    }
}