PHP Static variable inside a function not incrementing - php

Question

I'm trying to learn about static variables inside a function. So I created this:
<?php
// Create a function that has a counter
function counter_inside_function()
{
static $counter = 0;
++$counter;
return $counter;
}
// counter_inside_function() in a variable
$counter_function = counter_inside_function();
// Create a loop and place the function inside it
$count = 1;
while ($count < 11) {
echo $counter_function, '<br>';
// echo counter_inside_function(), '<br>';
$count++;
}
I was expecting to increment the counter but it didn't. However, if I uncomment line 21 and echo the function directly (not the $counter_function variable, that's when it incremented. What I don't get is it started counting from 2 instead of 1. But when I removed $counter_function = counter_inside_function(); I got the result I wanted.

Answer 1

You should move $counter_function = counter_inside_function(); inside your while loop so that the function is called on every iteration:
<?php
// Create a function that has a counter
function counter_inside_function()
{
static $counter = 0;
++$counter;
return $counter;
}
// Create a loop and place the function inside it
$count = 1;
while ($count < 11) {
$counter_function = counter_inside_function();
echo $counter_function, '<br>';
$count++;
}

Answer 2

When you call the function counter_inside_function() on line 13 and stored its return value into a variable what you've done is you've run that function one time and its returning 1. Now since the variable in counter_inside_function() is static its going to keep that value the next time you call it. That's why it seems as if its starting at 2 when really you've incremented it to 1 before the while loop and then during the loop it seems as though it is starting at 2.
Now the issue with the loop is that you echoing the variable $counter_function 20 times does not mean you're calling the function counter_inside_function() 20 times. All you're doing is taking the number that was stored in it the first call (which is 1) and echoing it out 20 times. So if you remove the comment on line 21 and remove the function call on line 13 (so that it doesn't increment to 1 before your loop begins) your program will give you the results you want.
This is how your code should look like:
// Create a function that has a counter
function counter_inside_function()
{
static $counter = 0;
++$counter;
return $counter;
}
// Create a loop and place the function inside it
$count = 1;
while ($count < 11) {
$counter_function = counter_inside_function();
echo $counter_function, '<br>';
$count++;
}