Newbie problem with function coding..

This is a discussion on Newbie problem with function coding.. within the C++ Programming forums, part of the General Programming Boards category; I posted a thread before, but I have recoded since. All my function prototypes are now in my header file, ...

  1. #1
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    Question Newbie problem with function coding..

    I posted a thread before, but I have recoded since. All my function prototypes are now in my header file, and their definitions are in my *.cpp file. The function I am having trouble with seems to freeze the program right after it outputs the "product code" letter I enter. I enter a letter, it outputs the upper case version of that letter, then nothing seems to happen. Here is the code again:

    Code:
    char accept_item_code ()
    {
       char c;
       
       cout << endl << "--------------------" << endl;
       cout << "Enter product code: ";
       cin >> c;
       c = toupper(c);
       cout << c;
       cout << endl;
       cout << "BEFORE WHILE LOOP";           // DEBUGGING
       while (c != 'A' && c !='B' && c !='C' && c !='D' 
            && c !='E' && c !='F'&& c !='G' && c !='H'
    		&& c !='I' && c !='X')
       {
          cout << "INSIDE WHILE LOOP";                 // DEBUGGING
          cout << "!!! Invalid product code" << endl << endl
               << "Enter product code: ";
          cin >> c;
          c = toupper(c);
          cout << endl;
       }
       cout << "RETURNING ITEM CODE FROM FUNCTION";   // DEBUGGING
    
       return c;
    }
    The prompt is printed, I enter the letter (like "a"), the toupper(c) changes it to "A", the "A" is printed to the screen, and then nothing more happens. What could be the problem? Any help is greatly appreciated since this program is due tonight!


    Josh Stevanus
    jrstevan@svsu.edu

  2. #2
    and the hat of wrongness Salem's Avatar
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    Well typing in 'A' means that the first test in your loop (c != 'A') is already false, which makes the whole boolean expression false, which means your while loop never executes.

  3. #3
    Toaster Zach L.'s Avatar
    Join Date
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    Logical or ( || ) may be the thing you are looking for.
    Playing around with the boolean operators for a short while will enable you to get the hang of them.
    The word rap as it applies to music is the result of a peculiar phonological rule which has stripped the word of its initial voiceless velar stop.

  4. #4
    Hardware Engineer
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    ...then nothing seems to happen...
    What is supposed to happen? What's the program/ function supposed to do? Is 'A' supposed to be valid, or invalid???


    1- You enter an 'a', which gets changed to a 'A' by toupper()

    2- 'A' is displayed

    3- The while condition is not met, so the while-loop is skipped. 'A' is valid (not invalid if you prefer).

    4- The function returns 'A'

  5. #5
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    Quote Originally Posted by jstevanus
    The prompt is printed, I enter the letter (like "a"), the toupper(c) changes it to "A", the "A" is printed to the screen, and then nothing more happens. What could be the problem? Any help is greatly appreciated since this program is due tonight!


    Josh Stevanus
    jrstevan@svsu.edu
    Sorry if you missed the deadline. For future reference: does it make any difference if you flush the output stream? Something like:

    Code:
       cout << "BEFORE WHILE LOOP" << flush;
    or

    Code:
       cout << "RETURNING ITEM CODE FROM FUNCTION" << endl;
    Regards,

    Dave

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