Case - random numbers without repetition (HashSet and TreeSet)

 

package com.it02;

import java.util.HashSet;
import java.util.Random;
import java.util.Set;
import java.util.TreeSet;

public class Demo {
    public static void main(String[] args) {

        //1. Create a collection object 
      //  Set<Integer> set = new HashSet<Integer>();
        Set<Integer> set = new TreeSet<Integer>();

        //2. Create random objects 
        Random r = new Random();

        //3. Judge whether the set length is less than 10
        while (set.size()<10){
           // Generate a random number and save it to the set 
           int number =  r.nextInt(20)+1;
           set.add(number);
        }

        //4. Ergodic set 
        for (Integer i: set) {
            System.out.println(i);
        }



    }
}