PHP使用while和嵌套for循环错误地循环输出

Question

Attempting to generate table columns and rows based on input. With smaller numbers it appears to work appropriately, for example inputting 2 rows and 3 cols. But when inputting slightly larger numbers like 5 for rows will output an incorrect amount of rows sometimes looping indefinitely.

if(isset($_POST['submit'])) {

    $rows = (int)$_POST['row_num'];
    $cols = (int)$_POST['col_num'];
    $n = 1;
    $e = 0;

    echo '<table id="">';

    while(($e < $rows) && ($e < $cols)) {

        for($i = 0; $i < $rows; $i++) {
            echo '<tr>';

            for($i = 0; $i < $cols; $i++) {
                echo '<td><input type="text" name="field_' . $n . '"></td>';
                $n++;
            }

            echo '</tr>';
        }

        $e++;
    }

    echo '</table>';
}

Answer 1

Firstly, you don't need the While loop, it's pointless and probably causing issues.

Secondly, you're using $i for both your rows and your columns, you can't use the same variable for both. Use $i for one and $j for the other. This should work:

if(isset($_POST['submit'])) {

    $rows = (int)$_POST['row_num'];
    $cols = (int)$_POST['col_num'];
    $n = 1;

    echo '<table id="">';

    for($i = 0; $i < $rows; $i++) {
        echo '<tr>';

        for($j = 0; $j < $cols; $j++) {
            echo '<td><input type="text" name="field_' . $n++ . '"></td>';
        }

        echo '</tr>';
    }

    echo '</table>';
}