eXtremely strange problem with amount indicator

This is a discussion on eXtremely strange problem with amount indicator within the C++ Programming forums, part of the General Programming Boards category; Look at this section of code: Before calling this, the varible quads is 50. Code: // Copy the wings to ...

  1. #1
    Unregistered User Yarin's Avatar
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    Exclamation eXtremely strange problem with amount indicator

    Look at this section of code:
    Before calling this, the varible quads is 50.
    Code:
       // Copy the wings to the other side now:
       for(x = 0, bWingsOut = FALSE; x < quads; x++) {
          if(quadEx[x] == XL_WING) bWingsOut = TRUE;
          if(bWingsOut) {
             if(quadEx[x] == XL_END) bWingsOut = FALSE;
             quadEx[quads] = quadEx[x]; // THIS LINE
             for(y = 0; y < 7; y++)
                quad[quads][y] = quad[x][y];
             quad[quads][1] = -quad[x][1];
             quads++;   }   }
    After I call this, quads becomes 3. Why?? I only alter quads for the greater once!
    The weird thing is, when I comment out THIS LINE, quads is what it's suppose to be.
    Please help.
    A class that doesn't overload all operators just isn't finished yet. -- SmugCeePlusPlusWeenie
    A year spent in artificial intelligence is enough to make one believe in God. -- Alan J. Perlis

  2. #2
    Unregistered User Yarin's Avatar
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    This is really strange; changing the code to
    Code:
       // Copy the wings to the other side now:
       for(x = 0, bWingsOut = FALSE; x < quads; x++) {
          if(quadEx[x] == XL_WING) bWingsOut = TRUE;
          if(bWingsOut) {
             if(quadEx[x] == XL_END) bWingsOut = FALSE;
             if(quadEx[x] != XL_WING) quadEx[quads] = quadEx[x];
             else z = quads;
             for(y = 0; y < 7; y++)
                quad[quads][y] = quad[x][y];
             quad[quads][1] = -quad[x][1];
             quads++;   }   }
       quadEx[z] = XL_WING;
    works.
    If anyone knows why it's doing this I would still like to know!
    A class that doesn't overload all operators just isn't finished yet. -- SmugCeePlusPlusWeenie
    A year spent in artificial intelligence is enough to make one believe in God. -- Alan J. Perlis

  3. #3
    carry on JaWiB's Avatar
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    Buffer overflow perhaps? Where is quadEx declared, and is its size at least 51?
    "Think not but that I know these things; or think
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    Of knowing what I ought."
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  4. #4
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    Have you stepped through it to see it change there? I see no reason why the value of quads should change to 3....

  5. #5
    The superhaterodyne twomers's Avatar
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    Indeed. Have you tried printing quad's value for each iteration and seeing it change? Or does 'x<quads' only run once?

    Is quad your own type? If so how do you pass into the [] operator? Reference? Do you change it?

  6. #6
    Unregistered User Yarin's Avatar
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    This loop only runs once durring init.

    I have already thought of buffer overflow, but as you can see my decs don't indicate anything of the sort.
    Code:
    #define XL_VECTOR   0
    #define XL_END      1
    #define XL_WING     2
    
    #define MAX_QUADS 300
    float quad[MAX_QUADS][7];
    int quadEx[MAX_QUADS];
    int quads, x, y, z;
    EDIT:
    The part that baffles me...
    Like I pointed out in my 2nd post, the error only happens when I try to assign quadEx[quads] to the value 2.
    Last edited by Yarin; 10-25-2007 at 03:19 PM.
    A class that doesn't overload all operators just isn't finished yet. -- SmugCeePlusPlusWeenie
    A year spent in artificial intelligence is enough to make one believe in God. -- Alan J. Perlis

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