The $GLOBALS do not get the expected data - php

Question

I have the bellow php code:
<form method="get">
<input type="text" name="num1" placeholder="num1">
<input type="text" name="num2" placeholder="num2">
<button type="submit" name="submit" value="func1">Submit</button>
</form>
The result is: <?php
if (isset($GLOBALS['result'])) {
echo $GLOBALS['result']; // there do not get the add result.
}
?>
<?php
$GLOBALS['result'] = 0;
if(isset($_GET['submit']) && $_GET['submit'] == 'func1'){
$num1 = $_GET['num1'];
$num2 = $_GET['num2'];
$GLOBALS['result'] = $num1 + $num2;
}
?>
The issue is if (isset($GLOBALS['result'])) {...} the code did not walk through.
Where is my issue?
Or how can I use a variables in different php tags?

Answer 1

Try below code
It is working.
<?php
session_start();
?>
<form method="get">
<input type="text" name="num1" placeholder="num1">
<input type="text" name="num2" placeholder="num2">
<button type="submit" name="submit" value="func1">Submit</button>
</form>
<?php
if(isset($_GET['submit']) && $_GET['submit'] == 'func1'){
$num1 = $_GET['num1'];
$num2 = $_GET['num2'];
$_SESSION['result'] = ($num1 + $num2);
}
?>
The result is: <?php
if (isset($_SESSION['result'])) {
echo $_SESSION['result']; // there do not get the add result.
}
?>

Answer 2

The page gets refreshed after submitting the form.
So the value get reset in GLOBALS.
If you can echo GLOBALS inside the submit condition then you will get the values.
Note : Use SESSION instead of GLOBALS.
<?php
if(isset($_GET['submit']) && $_GET['submit'] == 'func1'){
$num1 = $_GET['num1'];
$num2 = $_GET['num2'];
$GLOBALS['result'] = $num1 + $num2;
echo $GLOBALS['result'];
}
?>