ADT stack:set of elements of type elemtype (elemtype is used to refer to the type of the individual elements in a stack. Elemtype can potentially be any defined type * Stack-ADT Operations: procedure initialise(var S:stack); This procedure assigns an empty stack to S. ·定义栈的管理动作： procedure push(var S:stack;a:elemtype); Stack S should not be full.This procedure adds the element a at ·initialize(S):创建一个栈； the top of the stack. ·push(S,c:将c压入栈S中： procedure pop(var S:stack); Stack S should not be empty.The top element of the stack is ·top(S):栈顶元素； removed. ·pop(S):将栈顶元素去除； function top(S:stack):elemtype; ·empty(S):判定S是否为空 Stack S should be non-empty and this function returns the top element of the stack S.The stack S is left unchanged.(If elem- ·ful(s:判断S是否满 type is a structured type,this function should be rewritten as a procedure,see note 1 of section 3.1.) function empty(S:stack):boolean; This function returns true if S is empty and false otherwise. function full(S stack):boolean; If S is full this function returns a true value. Otherwise it returns a false value.Stack-ADT • 定义栈的管理动作： • initialize(S):创建一个栈； • push(S,c):将c压入栈S中; • top(S):栈顶元素； • pop(S):将栈顶元素去除; • empty(S):判定S是否为空 • full(s):判断S是否满