All binary operators (operators that come between two values), such as +, -, =, !=, ==, >, etc. should have a space before and after the operator, for readability. For example, an assignment should be formatted as $foo = $bar; rather than $foo=$bar;. Unary operators (operators that operate on only one value), such as ++, should not have a space between the operator and the variable or number they are operating on.