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Thread: I am a beginner please help :)

  1. #1
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    Default I am a beginner please help :)

    what wrong whit this statment:

    while(!code.equals(code1||code2||code3))
    {
    System.out.print("Ivalid code. Please enter code again: ");
    code = in.nextLine();
    }

    Error msg: bad operand types for binary operator

    thanks


  2. #2
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    Default Re: I am a beginner please help :)

    If you want help, you'll have to provide an SSCCE that demonstrates exactly what you're talking about. As of now we'd just be guessing. Don't forget the highlight tags.
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  3. #3
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    Default Re: I am a beginner please help :)

    My problem is that i wish that the while loops keeps looping until the 'code' inputted is equal to one of the pre-defined code: code1, code2, code3.

    System.out.print("CODE: ");
    code = in.nextLine();
    int quantity=0;

    while(!code.equals(code1||code2||code3))
    {
    System.out.print("Ivalid code. Please enter code again: ");
    code = in.nextLine();
    }

    So i guess !code.equals(code1||code2||code3 is not excepted by the program

  4. #4
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    Default Re: I am a beginner please help :)

    Again, without knowing exactly what you're talking about, I'm only guessing (and where are your highlight tags?), but I believe your problem lies in the syntax of a conditional:

    DON'T DO THIS: if(one == two || three)

    DO THIS INSTEAD: if(one == two || one == three)

    I'm using one, two, three, if, ||, and == for demonstrative purposes, but the lesson is this: && and || separate individual, full expressions, not just lists of values.
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  5. The Following User Says Thank You to KevinWorkman For This Useful Post:

    mvonb17 (February 6th, 2012)

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    Default Re: I am a beginner please help :)

    Sry for not being very clear to explain my problem. Hope i improve with time hehe.

    Ok thanks for your help. I knew that it works in this way but i thought that maybe another method might exist to save the user some lines. What if you have to compare with 50 other integers? Do you have to write the '!code.equals(coseX)' 50 times?

    Thanks again!

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    Default Re: I am a beginner please help :)

    Yeah, you would, however it seems that you should be checking an array, not a ton of variables. If you put code1, code2, code3....code50 all in a list, you could just do this:

    /*
     * PRECONDITION: list is not null and is of the same type of i,
     * which is also not null.
     */
    Collections.sort(list);
    int ind = Collections.binarySearch(list, i);
    if(ind >= 0)
    {
      System.out.println(i+" is in "+list+" at index "+ind);
    }else
    {
      System.out.println(i+" is not in "+list);
    }

  8. #7
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    Default Re: I am a beginner please help :)

    If it is for an array, u could also use a "for" or a do{...}while()

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    Default Re: I am a beginner please help :)

    Or you could do what I just said, which would have less code and most likely be more efficient.

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