PHP

Code for a PHP Times Table

 

 

The code for the Times Table in the previous page
uses a For Loop. The Start for the loop will come from the Start Number textbox,
and the end of the loop will come from the End Number textbox. Here’s the
code in full (without the HTML):

<?PHP

$times = 2;

if (isset($_POST[‘Submit1’])) {

$start = $_POST[‘txtStart’];
$end = $_POST[‘txtEnd’];
$times = $_POST[‘txtTimes’];

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

$answer = $start * $times;
print $start . ” multiplied by ” . $times . ” = ” . $answer
. “<BR>”;

}

}

?>

Code Explanation

We need all those numbers from the textboxes on the
form, so we start with:

$times = 2;

if (isset($_POST[‘Submit1’])) {

$start = $_POST[‘txtStart’];
$end = $_POST[‘txtEnd’];
$times = $_POST[‘txtTimes’];

}

The first line just puts a value in the variable called $times . This is
so that the “Multiply By” textbox will have a default value when
the page is loaded.

Next we use the isset( ) function again, just to check if the user
clicked the Submit button. This is exactly the same as you saw in the last
section.

To get the values from the textboxes, we use the following:

$start = $_POST[‘txtStart’];
$end = $_POST[‘txtEnd’];
$times = $_POST[‘txtTimes’];

Again, this is code you met in the last section. You just assign the values
from the textboxes to the new variables using $_POST[]. In between the square
brackets, we’ve typed the NAME of the HTML textboxes. So this gives us the
values that the user entered on the form. Next comes out For Loop:

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

$answer = $start * $times;

}

Let’s look at that first line again:

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

So we have a starting value for our loop, an end value, and an update expression.
The starting value is coming from the variable called $start. This will be
whatever number the user entered in the first textbox. The default is 1. Look
at the end value, though:

$start <= $end

The end value is when the value in the variable called $start is less than
or equal to the value held in the variable called $end. This works because
we’re increasing the value of $start each time round the loop. The variable
called $end is a fixed value, and comes from the textbox on the form.

The last part of the loop code is the update expression. This tells PHP to
increase the value of $start each time round the loop:

$start++

The double plus symbol (++) means “add 1 to the number held in $start”.

And that’s the essence of for loops: provide a start value, an end value,
and how you want to update each time round the loop.

The code inside the for loop, however, the code that gets executed each time
round the loop, is this:

$answer = $start * $times;

Remember, the variable $times holds the times table, the 2 times table by
default. This is being multiplied by whatever is inside the variable $start.
Each time round the loop, $start will have a different value – first
1, then 2, then 3, etc. The answer is then stored in the variable that we
called $answer. So it’s really doing this:

$answer = 1 * 2;
$answer = 2 * 2;
$answer = 3 * 2;
etc

Finally, we displayed the result to the page like this:

print $start . ” multiplied by ”
. $times . ” = ” . $answer . “<BR>”;

This is just concatenation. See if you can work out what all the parts do!

And that’s it – your very own times table generator. If you have
children, show them the programme you wrote. They’ll be very impressed
and tell you how brilliant you are. Children are like that.

Of course, your programme is not perfect, which I’m sure the children
will discover. Especially if they enter a 10 as the start number and a 1 as
the end number. Why doesn’t it print anything out? Anything you can do to
trap this error? Another if statement somewhere, perhaps?

|

Kaynak : https://www.homeandlearn.co.uk/php/php5p3.html ‘sitesinden alıntı

Yorum Yap