1

i need help for generating of unlimited strings from keyboard, but this don't work..

Scanner input = new Scanner(System.in);
    ArrayList<String> al = new ArrayList<String>();

     String check=null;
      while(true){
          check = input.nextLine();
          if(check == "stop") break;
          al.add(check);

      }
      System.out.println(al);
}

}

user2920764
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    `unlimited`? and `doesn't work`? I don't understand what you're trying to do or what problem you're having, but.... `if(check == "stop")` is almost definitely not doing what you want it to do. – nhgrif Oct 25 '13 at 16:22

2 Answers2

4
if(check == "stop")

This is wrong and should instead be written as:

if("stop".equals(check))
nhgrif
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2

To compare objects in java use .equals() method instead of "==" operator

Need to change 

if(check == "stop") break;

to

if("stop".equals(check)) break;
Prabhakaran Ramaswamy
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    While your answer is not wrong, it is my understand that `"stop".equals(check)` is slightly better because `check` could be null. – nhgrif Oct 25 '13 at 16:24
  • Np. :/ Except now your answer has more votes than mine. :( Haha. – nhgrif Oct 25 '13 at 16:28
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    If you're not worried about null then for fun you could also write it like this: `if (check.intern() == "stop")` By "for fun" I mean, "to drive your coworkers crazy" :) Seriously, though, if you understand how `intern()` works then you'll have a good understanding of how Strings work in Java, or at least why `==` doesn't always work but sometimes does. – Paul Oct 25 '13 at 16:43