Variable reference value in PHP learning Note _php Tutorial

Reference: means that the original object's address in memory is passed to the target object, which is equivalent to the same memory address that the original object and the target object point to. In this case, the data in memory will change if the target object or the original object is modified.

The so-called value passing means that only the value of the object is passed to the target object, which is equivalent to copy; The system will re-open an identical memory space for the target object.

The so-called reference, that is, to pass an object's in-memory address to the target object, is equivalent to making the target object and the original object correspond to the same memory storage space. In this case, the data in memory will change if the target object is modified.

If the value is a non-object, a copy of the value is passed, and any change to the variable does not affect the original value. A reference or an object is a real memory address, and changes made to that variable will affect the original value.

The code is as follows	Copy Code
function func1 ($a) {$a = $a + 1;} function Func2 (& $a) {$a = $a + 1;} $sample = 1; Func1 ($sample); Echo $sample; Output 1 $sample = 1; Func2 ($sample); 9.echo $sample; Output 2

Summarize

In high school, the teacher told us that the reference is to the memory address to the variable so long as the memory address changes and our accounting variables will change the content, this is a bit like a house put things, we can enter to take, as long as things change we go in to see things are the same, and not I put things in hand, So the things in the room changed and I don't change here.

http://www.bkjia.com/PHPjc/632649.html www.bkjia.com true http://www.bkjia.com/PHPjc/632649.html techarticle reference: means that the original object's address in memory is passed to the target object, which is equivalent to the same memory address that the original object and the target object point to. At this point, if the target object ...

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