java string validation for 3 choices

Question

I'm trying to make a user validation for multiple choices using a while loop and If the user doesn't match the choices then the program has to terminate. This is what I got so far

  while(input!="air" || input!="water" || input!="steel"){
        System.exit(0);
    }

Unfortunately, it doesn't work.

I would prefer to do exceptions, but my professor is strictly against using it for this assignment. I really want to grow as a programmer so any advice, tips and tricks are welcomed, thank you all for trying to help me out.

If the program should exit in case of a wrong input instead of asking for another one there is no point in using a `while` loop. — sinclair, Oct 04 '16 at 18:36

so-random-dude · Accepted Answer · 2016-10-04T19:03:06.050

-1

Change it as

while(!input.equals("air") && !input.equals("water") && !input.equals("steel")){
    System.exit(0);
}

Or

while(!(input.equals("air") || input.equals("water") || input.equals("steel"))){
    System.exit(0);
}

edited Oct 04 '16 at 19:03

answered Oct 04 '16 at 18:38

so-random-dude

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When would that condition ever be `false` ? – sinclair Oct 04 '16 at 18:41
That only solves one problem. Can you provide any `input` for which condition in `while` will be evaluated as `false`? Also what about first instruction in that loop. Does it make sense to loop it? – Pshemo Oct 04 '16 at 18:42
@Pshemo I overlooked that aspect! Just updated the answer. Thanks! – so-random-dude Oct 04 '16 at 19:04
@sinclair Just updated the answer. Thanks! – so-random-dude Oct 04 '16 at 19:05

java string validation for 3 choices

1 Answers1