Abstract Definition
A stack is a basic computer science data structure and can be defined in an abstract, implementation-free manner, or it can be generally defined as a linear list of items in which all additions and deletion are restricted to one end that is Top.
This is a VDM (Vienna Development Method) description of a stack:
Function signatures:
init: -> Stack push: N x Stack -> Stack top: Stack -> (N U ERROR) remove: Stack -> Stack isempty: Stack -> Boolean(where N indicates an element (natural numbers in this case), and U indicates set union)
Semantics:
top(init) = ERROR top(push(i,s)) = i remove(init) = init remove(push(i, s)) = s isempty(init) = true isempty(push(i, s)) = falseRead more about this topic: Stack (abstract Data Type)
Famous quotes related to abstract definition:
“What is important, then, is not that the critic should possess a correct abstract definition of beauty for the intellect, but a certain kind of temperament, the power of being deeply moved by the presence of beautiful objects.”
—Walter Pater (1839–1894)