Problem in loop. Please Help. Urgent!

This is a discussion on Problem in loop. Please Help. Urgent! within the C Programming forums, part of the General Programming Boards category; The code below will print out: Row: 0, Col: 0, p: 0, m: 0 Row: 0, Col: 1, p: 0, ...

  1. #1
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    Nov 2005
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    Problem in loop. Please Help. Urgent!

    The code below will print out:

    Row: 0, Col: 0, p: 0, m: 0
    Row: 0, Col: 1, p: 0, m: 0
    Row: 0, Col: 2, p: 0, m: 0

    Row: 1, Col: 0, p: 0, m: 0
    Row: 1, Col: 1, p: 0, m: 0
    Row: 1, Col: 2, p: 0, m: 0

    Row: 2, Col: 0, p: 0, m: 0
    Row: 2, Col: 1, p: 0, m: 0
    Row: 2, Col: 2, p: 0, m: 0

    Row: 0, Col: 3, p: 3, m: 0
    Row: 0, Col: 4, p: 3, m: 0
    Row: 0, Col: 5, p: 5, m: 0
    Row: 0, Col: 6, p: 5, m: 0
    Row: 0, Col: 7, p: 5, m: 0

    etc.

    Can someone please let me know why p suddenly changes to 5 (everything is fine before that). This is really annoying me and has to be sorted tonight.

    Thanks in advance.


    Code:
    int row, col, n, m, p, q;
      Cellgroup cgroup;
      Coord co;
      m = 0;
      p = 0;
      q = 0;
      n = 0;
    
    
    while(m<=6) {
          while(p<=6) {
              for(row=m; row<m+3; row++) {
                  for(col=p; col<p+3; col++) {
                      co.r = row;
                      co.c = col;
                      cgroup.grp[q] = co;
                      q++;
                      printf("Row: %d, Col: %d, p: %d, m: %d\n",row, col, p, m);
                  }
                  printf("\n");
              }
              group[n] = cgroup;
              n++;
              p+=3;
          }
          p=0;
          m+=3;
      }

  2. #2
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    Aug 2005
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    remove Cellgroup and coord, the program runs ok with VC++ 6.0 compiler. Maybe there is a buffer overflow in Cellgroup.grp array that is trashing memory.

  3. #3
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    Nov 2005
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    4
    Thanks that helped. But the thing is I am only meant to be using one global variable - group.

    I noticed it will work if you only take Cellgroup out of the method and leave Coord, however is there anyway you know of that I could keep both within the method?

  4. #4
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    Aug 2005
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    1,267
    post the Cellgroup structure. How big is the grp array? It should be something like this. Note that grp array must be at least 82, because the values of q range from 0 to 81.
    Code:
    struct Coord
    {
    	int r,c;
    };
    
    struct Cellgroup
    {
    	Coord grp[82];
    };

  5. #5
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    Oh yeh, i never noticed that before. thanks
    Last edited by jjbuchan; 11-10-2005 at 04:51 PM.

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