In reply to firstname.lastname@example.org:
Sorry, I don't understand your question.
There are two data types used as part of an associative array declaration, the type of each element, and the type of the index. You can use any type for both, including a class type.
"width" usually refers the number of significant bits that an integral type can represent. So if you have an associative array of bytes, the width of each element is 8, if you declare the index type as an int, the width of the index type is 32-bits. But there is no width associated with class types.