How to echo/print within a fuction with undefined variables in php? - php

Question

I am not the best at php but currently I am trying to learn. I can print fine outside of the function but the specific instructions I have been given require me to print the results within the function. I have tried
echo "$area";
echo "calculatearea ()";
ive searched but still cant figure out how to get a print within the function only outside of it.
<?php
if (isset($_POST['CalcBT'])) {
global $area;
function calculateCircumference () {
$num1 = ($_POST['Length']);
$num2 = ($_POST['Width']);
$circ = $num1 + $num2;
return $circ;
}
function calculateArea () {
$num1 = ($_POST['Length']);
$num2 = ($_POST['Width']);
$area = 2*($num1 + $num2);
return $area;
}
echo "Your rectangle circumference is: " . calculateCircumference() . '<br />' . "Your rectangle area is: " . calculateArea();
}
?>
<!---------------- Form---------------->
<div class="form">
<h3></h3>
<form action="PHP-sida4.php" method="POST">
<p>Length: <input type="text" name="Length"value=""></p>
<p>Width: <input type="text" name="Width"value=""></p>
<input type="submit" name="CalcBT" value="Calculate">
</form>
I need the return value of $area along with what I echo'd in the bottom to actually print within the first function ( calculateCircumference )

Answer 1

You can echo anything you want within the function but it won't show up until you call the function.
<?php
if (isset($_POST['CalcBT'])) {
global $area;
function calculateCircumference () {
$num1 = ($_POST['Length']);
$num2 = ($_POST['Width']);
$circ = $num1 + $num2;
// return $circ;
echo "Your rectangle circumference is: " . $circ . '<br />' . "Your rectangle area is: " . calculateArea();
return;
}
function calculateArea () {
$num1 = ($_POST['Length']);
$num2 = ($_POST['Width']);
$area = 2*($num1 + $num2);
return $area;
}
calculateCircumference();
}
?>
I hope this helps!

Answer 2

Okay if am getting your question right, to need to return the area and some other text along with the area.
Let's begin with some house cleaning, therefore the $area global variable could be renamed to something else like $results Which will be an array or object. Taking it simple.
Lets go with an associative array where e.g:
$results = [
'area' => null,
'text' = null
];
From that your will be updating $results['area'] from the calculate function and also update the $results['text'] before calling echo, so probably extract the echoed text to another variable.
And now you can access $results anywhere within the file with both the area and the text:
To just be more expressive under CalculateArea() function do something like:
$results['area'] = $area;
Same thing with the echoed text.

Answer 3

You can use echo instead of return in your functions. To call them, your can just use function(); without any additional keyword :
function calculateCircumference () {
$num1 = ($_POST['Length']);
$num2 = ($_POST['Width']);
$circ = $num1 + $num2;
echo $circ;
}
function calculateArea () {
$num1 = ($_POST['Length']);
$num2 = ($_POST['Width']);
$area = 2*($num1 + $num2);
echo $area;
}
echo "Your rectangle circumference is: " ;
calculateCircumference() ;
echo '<br />' ;
echo "Your rectangle area is: " ;
calculateArea();

Answer 4

You can echo anything anywhere, be it inside a function or outside of it. If an echo is not performing, then there was either an error, or the line where the echo can be found was not executed.
In our case you have removed the echo after your functions, which, coincidentally happened to be the only place where they were called.