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PHP PHP Basics Unit Converter Arithmetic Operators

Ty Mckenzie
Ty Mckenzie
3,465 Points
Posted by Ty Mckenzie
Ty Mckenzie
3,465 Points

Why does var_dump(a$--); not subtract 1?

$a = 5;

$b = 10;

$a = $a + 1;

var_dump($a); <---- = int(6)

$a++;

var_dump($a); <---- = int(7)

$a--;

var_dump($a); <---- = int(6)

var_dump($a--); <---- = int(6) Why isn't this 5?

var_dump($a); <---- = int(5)

var_dump(--$a); <---- = int(4)

var_dump($a); <---- = int(4)

Console

int(6)
int(7)
int(6)
int(6)
int(5)
int(4)
int(4)

1 Answer

Steven Parker
Steven Parker
231,248 Points
Steven Parker
Steven Parker
231,248 Points

It does subtract, the issue is just when.

When you write --$a, that's the predecrement operator. It subtracts one before returning the value.

But $a-- is the postdecrement operator, it subtracts one after returning the value.

For more details, see the PHP documentation.

Ty Mckenzie
Ty Mckenzie
3,465 Points
Ty Mckenzie
Ty Mckenzie
3,465 Points

Ahhh of course. Thanks!