Ask a basic question, can you show the declaration variables

Ask a basic question, can you show the declaration variables?
If you use a variable in a function class
$c = "AAA";
The engine is to go to the global find this variable, can not find and then create it?

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What does it mean?? If you can't find it, you can't find it. You're looking for $c in the function. That's a local variable, and he's not going to make a claim to find the whole thing or create it automatically. If you use it, there's no one there.
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Does PHP have a display and an implicit declaration? I don't know.
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Statement to Global
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Yes, that's global!.
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Global $aaa; A global variable is declared in a class, but can be used without global variables in a class, so reusability is not high, and debugging a global variable is more troublesome than a local variable.
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Unless declared as global, the default is local, and PHP is different.
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Global meaning I'm going to use this variable now, I've already defined it in "somewhere else."
and $globals[' var ') are generally the same effect
PHP definition is much different from C + + Java
$c = "AAA", if there is "AAA" in memory
Might just be a pointer to not declaring AAA

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