PHP 时间表创建

Question

Hi I'm trying to figure out some code in PHP, I've been given the task to make a basic times table input, I have that part figured out. I have also to reverse the order the table is being output. So instead of the example running from 1 x 10=10 down I have to reverse that order from 10 x 10=100 down instead. This part I can't figure out. output

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

$start = $_POST['startNumber'];
$end = $_POST['endNumber'];
$times = $_POST['times'];

for($start; $start <= $end; $start++) {

    $answer = $start * $times;
    echo $start, " x ", $times, " = ", $answer, "<BR>";
    }
}

Answer 1

You can just push to an array instead, reverse the array after the loop, join the array into a string, then echo the output.

Also be careful with user submitting input. In this case I believe you're expecting ints so I typecasted them for you.

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

$start = (int)$_POST['startNumber'];
$end = (int)$_POST['endNumber'];
$times = (int)$_POST['times'];

$out = [];
for(; $start <= $end; $start++) {

    $answer = $start * $times;
    $out[] =  "$start x $times = $answer<br>";
    }
}
$out = array_reverse($out);
echo implode('',$out);

Alternatively, you can just walk the loop in reverse:

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

$start = (int)$_POST['startNumber'];
$end = (int)$_POST['endNumber'];
$times = (int)$_POST['times'];

for(; $end >= $start; $end--) {

    $answer = $end * $times;
    echo "$end x $times = $answer<br>";
    }
}

Answer 2

The easiest way I can think of is to create an array with range and then reverse it using array_reverse . With that, you can simply iterate over the numbers and do your calculations.

Demo, http://sandbox.onlinephpfunctions.com/code/98ab6864cffb764325ea6b4a2f2f74178e13c62b

<?php

$start = 1;
$end = 10;
$multiplier = 10;

$reversed = array_reverse(range($start, $end));

foreach ($reversed as $input) {
    echo sprintf('%s x %s = %s %s', $input, $multiplier, $input * $multiplier, "\n");
}

Answer 3

You could tweak your original code, but rather than output it straight away add it to the current output at the start. The output the result at the end

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

    $start = $_POST['startNumber'];
    $end = $_POST['endNumber'];
    $times = $_POST['times'];

    $output = '';
    for($start; $start <= $end; $start++) {
        $answer = $start * $times;
        $output =  $start . " x " . $times ." = " . $answer . "<BR>" . $output;
    }
    
    echo $output;
}