javascript - Why the prevoius value still exists after reinitialaize variable - PHP

Question

I came across a tutorial and when we reinitialize a variable that has a value , instead of removing the value , the variable still has the previous value .

I the 3 rd var_dump i am expecting NULL , but it prints volvo . isn't this creating confusing things in the code .

$carName;
var_dump($carName);

$carName = "Volvo";
var_dump($carName);

$carName; 
var_dump($carName);



NULL
string(5) "Volvo"
string(5) "Volvo"

I also saw that javascript has the same behavior .

Is this a good feature of the language or a bad feature . According to my idea , this is bad , please explain . thanks in advance .

Answer 1

$carname; does not in fact do anything. It's neither using the variable for any operation, nor is it assigning anything to it. In PHP variables are "initialised" by assigning something to them. If anything, $carname; is the same as echo $carname; without the echo, it's just a NOOP. In fact, the first line doesn't do anything either, the first var_dump triggers an Undefined variable carname notice.