What is happening with this code??

This is a discussion on What is happening with this code?? within the C++ Programming forums, part of the General Programming Boards category; I have this function that is meant to draw the highscores using a class called fileHandler which manages the highscore.txt ...

  1. #1
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    Apr 2012
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    What is happening with this code??

    I have this function that is meant to draw the highscores using a class called fileHandler which manages the highscore.txt file.

    For some reason which I cannot see right now, when I step through the code I notice that the values for scoreList (which contain a structure called scoreData that consist of a string and a int for the score) are changing in the introduction for the for loop.

    It goes from having a empty string and a integer holding 6 to a really small integer, like when a value is uninitialized, and a string with a bad pointer.

    How is this being altered?????

    Code:
    void menu::drawScoreBoard(void)
    {
    ///////////////////////////DRAW THE SCORE BOARD HERE//////////////////////////////////////////////////////////////////
        fileHandler scoreFile;
        std::vector <dataType::scoreData *> scoreList;
        std::string temp;
        int count = 1;
    
        if (scoreFile.getScore(&scoreList))
        {
            for (std::vector<dataType::scoreData *>::iterator it = scoreList.begin(); it < scoreList.end(); it++) //error here
            {
                temp = drawArea->IntToStr(count) + ") " + (*it)->initials + drawArea->IntToStr((*it)->score);
                drawArea->drawMessage(temp, scoreBoardPos.x, scoreBoardPos.y +count);
                count++;
            }
        }
    }

  2. #2
    and the hat of int overfl Salem's Avatar
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    Code:
        std::vector <dataType::scoreData *> scoreList;
        std::string temp;
        int count = 1;
     
        if (scoreFile.getScore(&scoreList))
    Is this just filling in a vector with a load of pointers to memory that no longer exists (say local vars in getScore()) ?

    Forget the pointers and trying to make it "efficient", and get it working by making a regular copy of the data.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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  3. #3
    a_capitalist_story
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    Not to mention, if you're populating a vector, then the method name getScore() is confusing, because it's actually getting a list of scores, as the variable itself states clearly. Better to make that method getScores(std::vector<dataType::scoreData *> &scoreList) or getScoreList(std:vectordataType::scoreData *> &scoreList)

  4. #4
    Registered User
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    I forgot the pointers like you said and it worked like a treat, thanks!

    @rags_to_riches Noted, I have been slightly changing functions around without changing the name.

    Thanks for the help!

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