Random method

output:1~10

import java.util.Random;
public class Random_test {
    public static void main(String[] args){
        Random r=new Random();
        int num;
        num=r.nextInt(10);
        System.out.println(num+1);
    }


}

 2.gambling numbers

package Gambling_numbers;
import java.util.Random;
import java.util.Scanner;
public class 赌数字 {
    public static void main(String [] args){
        Random r=new Random();
        int num1=r.nextInt(15);
        System.out.println("Start gambling!");
        Scanner sc=new Scanner(System.in);
        int num2=sc.nextInt();
        if(num1<5) {
            System.out.println("smaller than 5");
        }else if(num1>=5&&num1<10){
            System.out.println("smaller than 10 and bigger than 5");

        }else{
            System.out.println("else");
        }
        while(num1!=num2){
            System.out.println("false");
            System.out.println("next");
            int num3=sc.nextInt();
            num2=num3;
        }
        if(num1==num2){
            System.out.println("bingo");
        }

    }
}

 3.example