Index handler

Representation invariant

At any time, an object of an implementation of this abstract data structure is repesented by a positive integral number [math]\displaystyle{ N }[/math] and a subset [math]\displaystyle{ I }[/math] of [math]\displaystyle{ \{1,\ldots,N\} }[/math], the current indexes.

Method

Name: reserve index

Precondition: [math]\displaystyle{ |I|\lt N }[/math].

Return value: One of the indexes not in [math]\displaystyle{ I }[/math].

Postcondition: The returned index is inserted in [math]\displaystyle{ I }[/math].

Method

Name: release index