Character array initialization problem

This is a discussion on Character array initialization problem within the C Programming forums, part of the General Programming Boards category; Hello, I have a character array with 14 elements in my newest version of my program. The same character array ...

  1. #1
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    Character array initialization problem

    Hello,

    I have a character array with 14 elements in my newest version of my program. The same character array is on the same spot in my old version of the program.
    The differences are: On my old version the array gets initialized with 0s. On my new one it has some random negative numbers in it.

    This is ALWAYS the case. Not matter how often I restart both programs.
    I have the feeling that some evil pointer is overriding the array element values. But that's just a feeling. I ran the program several times now and it executed like expected.

    Any idea what this could be?

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    So your guess is that it has something to do with a pointer, and now you want us to guess?

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    Where is the array defined? Inside a function or outside up top in "global" space?
    My guess is it's inside a function. If you don't explicitly initialize it, it will have garbage (unpredictable crap) in it.

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    Please post your code in [code] tags

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    No,

    I want to know the known reasons why an array is initialized with 0s in one program and the same one is initialized with numbers in the same program, but newer version.

    I am pretty sure now that it is no pointer problem, as I commented out all new pointers and had the same problem.

    The array is in a function (local). But why the difference between the two program versions?

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    Unless you're going to help us by showing us relevant portions of the old and new program, then all I can say is perhaps the storage class of the variable changed (static to automatic). You can read the C standard on variable initialization. There is a sticky post here with info on the C standard: C Draft Standards. I suggest using the top link and looking through section 6.7.8. You can also find information about static variables and automatic variables on wikipedia.

  7. #7
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    Quote Originally Posted by ThatDudeMan View Post
    I have the feeling that some evil pointer is overriding the array element values. But that's just a feeling.
    You need to post some code or we can only guess.

  8. #8
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    If it's in a local function, an uninitialized array (and I'm just guessing that's where your bug is) results in any undefined values residing there. It's stack. So it is left over stuff from previous stack use. Any change in program flow or the values of previous parameter passing from unrelated calls would affect which values are put there.

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