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Thread: A simple mistake I can't fix

  1. #1
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    Default A simple mistake I can't fix

    String userInput;

    int lowerCase = 0, upperCase = 0;
    Scanner scan = new Scanner (System.in);

    System.out.println("Enter a word (type exit to finish) : ");

    userInput = scan.next();

    while (userInput != exit){


    for (int i = 0; i<userInput.length(); i++){
    for (char lower = 'a'; lower <= 'z'; lower++){
    if (userInput.charAt(i) == lower){
    lowerCase++;
    }
    }
    }

    for (int j=0; j<userInput.length(); j++) {
    for(char upper='A'; upper<='Z'; upper++) {
    if (userInput.charAt(j) == upper)
    {
    upperCase++; }
    userInput = scan.next();
    }
    }
    }
    System.out.println("Total number of lower case letters = " + lowerCase);
    System.out.println("Total number of upper case letters = " + upperCase);

    }

    }


    Error result
    Exception in thread "main" java.lang.Error: Unresolved compilation problem:
    exit cannot be resolved to a variable

    at Q3.main(Q3.java:19)


    How do I fix this?


  2. #2
    Super Moderator jps's Avatar
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    Default Re: A simple mistake I can't fix

    First, please put [code=java] before your code and [/code] after your code.

    Second the error message tells you what is wrong and points you to the general location of the error.
    exit cannot be resolved to a variable
    That means you typed the 4 letters exit somewhere (see below) and the compiler has no idea what those letters mean.

    at Q3.main(Q3.java:19)
    That means line 19 in your source code.

    From what I see, the line is:
    while (userInput != exit){

    edit:
    Since this syntax error is not your only problem, here is some suggested reading.
    Last edited by jps; September 5th, 2012 at 03:27 AM.

  3. #3
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    Default Re: A simple mistake I can't fix

    Hello,
    Thanks for your insight. The only problem my program has is the while loop. The program should keep on asking userInput and calculate uppercase and lowercase characters until the user types in exit. But the program shouldn't calculate the uppercase and lowercase characters of the word exit when user inputs exit. Should I assign exit to a string s1 and replace the while loop as

    while (userInput != s1)

    The program runs fine if there isn't a while loop but I need it

  4. #4
    Super Moderator jps's Avatar
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    Default Re: A simple mistake I can't fix

    The only reason it would process the word "exit" is if your code inside the while loop runs, correct?
    That means the line of code to determine when to stop looping has not decided it is time to stop yet, correct?
    Looking at the line of code responsible for making this decision:
    while (userInput != s1)
    ...I refer you back to the suggested reading in my post#2 to see why this is happening. It has something to do with != and comparing strings.
    If you can't figure it out with that page, try searching "java compare strings"

  5. The Following User Says Thank You to jps For This Useful Post:

    xdx (September 5th, 2012)

  6. #5
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    Default Re: A simple mistake I can't fix

    Thanks a lot as I have figured out that the problem was using the != assignment, Should have used !userInput equals(exit).
    Also, I do want to apologise to all the viewers, especially jps for not coding my first post.

  7. #6
    Super Moderator jps's Avatar
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    Default Re: A simple mistake I can't fix

    Glad you got it working

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