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- Null vs. False vs. 0 in PHP 18 answers
- PHP considers null is equal to zero 11 answers
I never knew that PHP (at least ver. 5.6.25) considers NULL as 0 while performing simple arithmetic operations.
Recently, while hunting for the cause of a bug, I came across this. A simple test (indeed) confirms this:
$a = null;
echo $a + 1; // 1
echo $a - 1; // -1
echo $a * 1; // 0
echo $a / 1; // 0
echo 1 / $a; // INF (**E_WARNING : type 2 -- Division by zero**)
From my "limited" knowledge of C, NULL is (void *)0. Now, my guess is that PHP "magic" type casting is somehow casting void * to int *?!!
Why did PHP do this?
Isn't such "magic" casting (of null) something which should have been left for explicit conversions?
What exactly is happening here (if my guess was wrong)?
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