Printing an 4x4 grid and storing it in an array?

This is a discussion on Printing an 4x4 grid and storing it in an array? within the C Programming forums, part of the General Programming Boards category; Hi guys, I'm new here and I'm fairly new to C. This maybe simple to most of you guys but ...

  1. #1
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    Printing an 4x4 grid and storing it in an array?

    Hi guys, I'm new here and I'm fairly new to C.

    This maybe simple to most of you guys but I'm extremely frustrated because I don't know what to do with it at all.

    The problem is, I want to print out a pattern of this type:

    Code:
    +---+
    |   |
    |   |
    +---+
    and then storing this in an array so that when a user types in 4,3 it should point to board[4][3]. The grid size is supposed to be 8x8 but in the interest of simplicity, I'm going to start with a 4x4 grid.

    The problem is, I don't know how to print out that 4x4 grid with that pattern and I don't know how to store it in the array. Can someone please point me in the right direction?

    If you want to see some coding, all I have for now is this:

    Code:
    #include <stdio.h>
    #include <string.h>
    
    char board[4][4];
    
    int main() {
    
        for (int i = 0; i < 4; i++) {
            for (j = 0; j < 4; j++) {
                board[i][j] = 
            }
        }
    I'm really stuck as to what to input for board[i][j] and I'm unsure if that would even solve that problem...

    Thanks in advance!

  2. #2
    Gawking at stupidity
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    Personally, I would handle the first and last rows separately:
    Code:
    for(i = 0;i < width;++i)
      board[0][i] = (i == 0 || i == width - 1) ? '+' : '-';
    for(i = 1;i < height - 1;++i)
      for(j = 0;j < width;++j)
        board[i][j] = j == 0 || j == width - 1) ? '|' : ' ';
    for(i = 0;i < width;++i)
      board[height - 1][i] = (i == 0 || i == width - 1) ? '+' : '-';
    Something like that should work anyway. I didn't compile or test it.
    If you understand what you're doing, you're not learning anything.

  3. #3
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    Hmm I don't really understand that...

    Also what are the ? and : for?

  4. #4
    Gawking at stupidity
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    Okay, how about this then?
    Code:
    for(i = 0;i < height;++i)
    {
      if(i == 0 || i == height - 1)
      {
        // Print the first / last rows
      }
      else
      {
        // Print the other rows
      }
    }
    If you understand what you're doing, you're not learning anything.

  5. #5
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    So by first/ last rows you mean

    Code:
    +---+
    
    
    +---+
    that?

  6. #6
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    Yup.
    If you understand what you're doing, you're not learning anything.

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    Okay but I don't get how I would store it in the array.

    I mean, I get that if row is 0 or 3 in this case, it would output the first and last rows and the else statement is for the middle. But how would I go about storing that one "Box" in the board array, say for example board[1][1]?

  8. #8
    Gawking at stupidity
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    You'd determine what character goes in that position based on the values of i and j. if the current column is 0 or width - 1, then the character is '+' if the current row is 0 or height - 1, otherwise it's a '|', etc.

    Code:
    for each i in rows
    {
      if i equals 0 or i equals height - 1
      {
        for each j in columns
        {
          if j equals 0 or j equals width - 1
            board[i][j] = '+'
          else
            board[i][j] = '-'
        }
      }
      else
      {
        for each j in columns
        {
          if j equals 0 or j equals width - 1
            board[i][j] = '|'
          else
            board[i][j] = ' '
        }
      }
    }
    If you understand what you're doing, you're not learning anything.

  9. #9
    msh
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    First, I would declare an array of appropriate size, accounting for edges. Like so.
    Code:
    #define GRIDH (8 + 2)
    #define GRIDW (8 + 2)
    
    char grid[GRIDH][GRIDW];
    Then I would initialize the array, using a function like this.
    Code:
    #define CN '+'
    #define HL '-'
    #define VL '|'
    #define BL ' '
    
    void init_grid(int h, int w, char new_grid[GRIDH][GRIDW])
    {
      int i, t;
      for (i = 0; i < h; ++i)
      {
        for (t = 0; t < w; ++t)
        {
          if ((i == 0 || i == (h - 1)) && (t == 0 || t == (w - 1))) /* corners */
            new_grid[i][t] = CN;
          else if (i == 0 || i == (h - 1)) /* top and bottom edges */
            new_grid[i][t] = HL;
          else if (t == 0 || t == (w - 1)) /* side edges */
            new_grid[i][t] = VL;
          else                             /* we're in the clear */
            new_grid[i][t] = BL;
        }
      }
    }
    Then I would use this initialized grid to place a cursor based on user input, which would probably be defined as a structure holding XY coordinates. Before placing the cursor on the board, I would check if it is within bounds of the board.

    It's up to you to implement this in a complete program.
    Disclaimer: This post shows my ignorance at the time of its making. I claim ownership of but not responsibility for all errors in it. Reference at your own peril.

  10. #10
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    Quote Originally Posted by itsme86 View Post
    You'd determine what character goes in that position based on the values of i and j. if the current column is 0 or width - 1, then the character is '+' if the current row is 0 or height - 1, otherwise it's a '|', etc.

    Code:
    for each i in rows
    {
      if i equals 0 or i equals height - 1
      {
        for each j in columns
        {
          if j equals 0 or j equals width - 1
            board[i][j] = '+'
          else
            board[i][j] = '-'
        }
      }
      else
      {
        for each j in columns
        {
          if j equals 0 or j equals width - 1
            board[i][j] = '|'
          else
            board[i][j] = ' '
        }
      }
    }
    I tried that but it doesn't seem to work. Maybe I'm using a wrong printf conversion?

    If I wanted to test that out, would I use

    printf("%s", board);

  11. #11
    ATH0 quzah's Avatar
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    You need to either make it into a string, or you need to print each character one at a time.


    Quzah.
    Hope is the first step on the road to disappointment.

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