The $ operator in PHP is used to declare a variable. In PHP, a variable starts with the $ sign followed by the name of the variable. For example, below is a string variable:
$var_name = "Hello World!";
The $var_name is a normal variable used to store a value. It can store any value like integer, float, char, string etc. On the other hand, the $$var_name is known as reference variable where $var_name is a normal variable. The $$var_name used to refer to the variable with the name as value of the variable $var_name.
Input : $Hello = "Geeks for Geeks" $var = "Hello" echo $var echo $$var Output : Hello Geeks for Geeks Input : $GFG = "Welcome to GeeksforGeeks" $var = "GFG" echo $var echo $$var Output : GFG Welcome to GeeksforGeeks
Explanation: In the above example, $var stores the value “Hello”, so $$var will refer to the variable with name Hello i.e., $Hello.
Below program will illustrate the $ and $$ operator in PHP.
Hello GeeksforGeeks GFG Welcome to GeeksforGeeks
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