编写一个Java程序，查询用户一系列单词。 当用户输入“退出”时程序退出

Question

QUES Write a java program that queries the user for a series of words. The program exits when the user enters quit . Before the program exit, it should display all the list of words being entered.

I have tried solving this ques but when the list of the word is displayed the spaces left for the array is also printed. Am new in java programming so please help me.

import java.util.Scanner;
class ques1
{
    public static void main(String[] args)
    {
        String [] str=new String[20];
        Scanner sc=new Scanner(System.in);
        System.out.println("enter series of words and to exit write quit");
        int i=0;
         while(true){
                str[i]=sc.nextLine();
                    if(str[i].equals("quit") || str[i].equals("QUIT"))
                       break;
                    else
                        i++;
        }
        System.out.println();
        System.out.println("----------------------------");
        for (int j=0;j<str.length;j++)
        {
          System.out.println(str[j]);
        }     
    }
}

Answer 1

use ArrayList<String> it's a dynamic array and is more suitable for this functionality

ArrayList<String> words = new ArrayList<>();
while(true){
  String word = sc.nextLine();
  if (!word.toLowerCase().equals("quit"))
    word.add(word);
  else
    break;
 }

for(String word : words)
  System.out.println(word);

Answer 2

Arrays have fixed space allocated (in your case is 20) filled with null and will will produce ArrayIndexOutOfBounds if the user enter more than 20 words.

Expect that, since you are storing the index of the last inserted array element you can simple loop from 0 to i that are the only filled spaces of the array:

    for (int j=0; j <= i; j++) {
      System.out.println(str[j]);
    }