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Thread: another question..

  1. #1
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    Cool another question..

    can someone take a look at the api for the String class and tell me what methods are good for doing a do- while loop to make sure the user put in more than nothing for the program to continue.
    do
        {
        System.out.println("Enter a card and its suit like this: 4S");
        card = in.nextString();
     
        }
    while (in.equals > null)
    wow that makes no sense lol but i hope you understand the "data entry check" for the program to go on.
    Last edited by helloworld922; January 27th, 2010 at 12:34 AM. Reason: Please use [code] tags!


  2. #2
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    Default Re: another question..

    I'm going to assume that in is a Scanner object. There's no equals field/variable in the Scanner method. However, there is an equals method (very big difference). For the compiler to recognize it as a method, you must use parenthesis following the variable name (I believe white spaces are ignored).

    Secondly, Java does not support operator overloading, and by default the > operator is only defined for certain primitive data types (numbers, characters, which basically are numbers). If you want to see if that object contains something other than null, use the not or not equals method:
    while (someVar != null)

    You will also need a semi-colon after the while conditional statement because it is a do-while loop.

    The last major thing I see wrong is that you're trying to compare the Scanner object to see if it's null, not the string you read in. The scanner object should have some non-null value because it can be used to read from the stream. Further more, I'm guessing that you're reading from a user typing stuff in. This stream is never empty, but rather waits for the user to type something else in. You will need some sort of "keyword" to tell the program to stop, say quit:
    do
    {
         System.out.println("Enter a card and it's suit like this: 4S or quit to exit");
         card = in.nextString();
    } while (!"quit".equalsIgnoreCase(card));

  3. The Following User Says Thank You to helloworld922 For This Useful Post:

    etidd (January 27th, 2010)

  4. #3
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    Default Re: another question..

    okay, i seem to have gotten it... there's only one other issue with the logic of my program.