Question

What is the difference between $this->id and $id.

class Test{
 public $id;

 function Test(){
  $this->id = 1;
 }
}

===

class Test{
 public $id;

 function test(){
  $id = 1;
 }
}

how to get the variable from other class?

class TestA{
 public $test;

 function TestA(){
  $this->test = new Test();
  echo $this->test->id;
 }
}

Answer 1

php doesn’t work in a way C++, Java and C# work.

In php you should always use $this reference and -> operator to access the instance variables.

So the first code assigns 1 to the instance id property, and in the second you’re assigning 1 to a local $id variable.