Question

My question is instead of using coordinates to move can i assign numbers and letters so i can move with those values

Edit: I am outputting the board to html 8×8 table

$square = array( //    A B C D E F G H     
               0 array(0,0,0,0,0,0,0,0),
               1 array(0,0,0,0,0,0,0,0),
               2 array(0,0,0,0,0,0,0,0),
               3 array(0,0,0,0,0,0,0,0),
               4 array(0,0,0,0,0,0,0,0),
               5 array(0,0,0,0,0,0,0,0),
               6 array(0,0,0,0,0,0,0,0),
               7 array(0,0,0,0,0,0,0,0),
);

so when the user inputs : From: F1 to: G2 the pieces move

wouldn’t it be better is i do this

Array ( 'A' => Array ( [0] => 0 [1] => 0 [2] => 0 [3] => 0 [4] => 0 [5] => 0 [6] => 0 [7] => 0 ) 
        'B' => Array ( [0] => 0 [1] => 0 [2] => 0 [3] => 0 [4] => 0 [5] => 0 [6] => 0 [7] => 0 ) 
        'C' => Array ( [0] => 0 [1] => 0 [2] => 0 [3] => 0 [4] => 0 [5] => 0 [6] => 0 [7] => 0 ) 
        'D' => Array ( [0] => 0 [1] => 0 [2] => 0 [3] => 0 [4] => 0 [5] => 0 [6] => 0 [7] => 0 ) 
        'E' => Array ( [0] => 0 [1] => 0 [2] => 0 [3] => 0 [4] => 0 [5] => 0 [6] => 0 [7] => 0 ) 
        'F' => Array ( [0] => 0 [1] => 0 [2] => 0 [3] => 0 [4] => 0 [5] => 0 [6] => 0 [7] => 0 ) 
        'G' => Array ( [0] => 0 [1] => 0 [2] => 0 [3] => 0 [4] => 0 [5] => 0 [6] => 0 [7] => 0 ) 
        'H' => Array ( [0] => 0 [1] => 0 [2] => 0 [3] => 0 [4] => 0 [5] => 0 [6] => 0 [7] => 0 ) 

    ); 

parseSquareFrom

function parseSquareFrom() {
    if (strlen($square) != 2) {
    return FALSE;
    }

    $coords = array(ord('A') - ord($square[0]),
            $square[1] - 1);


    // Perform bounds-checking.
    if ($coords[0] < 0 || $coords[0] > 7 || $coords[1] < 0 || $coords[1] > 7) {
    return FALSE;
    }

    return $coords;
}
$coords = parseSquare($square);
if ($coords === FALSE) {
    // Invalid input, handle this case.
} else {
    $piece = $board[$coords[0]][$coords[1]]; // for example
}

and parseSquareTo

function parseSquareTo() {
    if (strlen($square1) != 2) {
    return FALSE;
    }

  $coords1 = array(ord('A') - ord($square1[0]),
            $square1[1] - 1);


    // Perform bounds-checking.
    if ($coords1[0] < 0 || $coords1[0] > 7 || $coords1[1] < 0 || $coords1[1] > 7) {
    return FALSE;
    }

    return $coords1;
}

$coords1 = parseSquare($square);
if ($coords1 === FALSE) {
    // Invalid input, handle this case.
} else {
    $piece = $board[$coords1[0]][$coords1[1]]; // for example
}

can i use that with this code

    $board[$coords1[0]-1][$coords1[1]+1] = $board[$coords[0]][$coords[1]];
    $board[$coords[0]][$coords[1]] = 0;

    //eating action
    $board[$coords1[0]][$coords1[1]] = 0;
    $board[$coords1[0]-2][$coords1[1]+2] = $board[$coords[0]][$coords[1]];

    //if player is 'up' then the value of $way is 1 so
      $board[$x+(-1*$way)][$y+(1*$way)] = $board[$coords[0]][$coords[1]]; // position 2,2 becomes 1,3
   //if player is not 'up' then the value of $way is -1 so
      $board[$x+(-1*$way)][$y+(1*$way)] = $board[$coords[0]][$coords[1]]; // position 2,2 becomes 3,1

or is the $piece = $board[$coords1[0]][$coords1[1]]; cannot be used

Answer 1

Yes: Parse the input string into an X,Y pair. For example:

function parseSquare($square) {
    if (strlen($square) != 2) {
        return FALSE;
    }

    $coords = array(ord('A') - ord($square[0]),
                    $square[1] - 1);

    // Perform bounds-checking.
    if ($coords[0] < 0 || $coords[0] > 7 || $coords[1] < 0 || $coords[1] > 7) {
        return FALSE;
    }

    return $coords;
}

So given a square string like $square = "F5";

$coords = parseSquare($square);
if ($coords === FALSE) {
    // Invalid input, handle this case.
} else {
    $piece = $board[$coords[0]][$coords[1]]; // for example
}