Post-increment, which is written '$variable++' evaluates to the original value of $variable, before it was incremented (PHP increments the variable after reading its value, thus the name'post-increment').
A very common type of expressions are comparison expressions. These expressions evaluate to either 0 or 1, meaning FALSE or TRUE (respectively). PHP supports (bigger than), = (bigger than or equal to), == (equal), != (not equal), (smaller than) and = (smaller than or equal to). These expressions are most commonly used inside conditional execution, such as if statements.