What is the meaning of ${$max} in PHP?

In PHP, ${$max} is a variable variable that allows you to dynamically create variable names based on the value of another variable. This can be useful when you need to access variables dynamically or when you want to create a large number of variables in a loop. To use ${$max}, simply assign a value to the variable $max and then access the dynamically created variable using ${$max}. Example: $max = 'num'; ${$max} = 10; echo $num; // Output: 10