Stack Information for CS2

• Definition of the stack data type
  • Organization -- Last-In, First-Out
  • Elements -- any given homogeneous set
  • Operations
    • constructor(s)
    • destructor(s)
    • bool StackIsEmpty()
    • void Push(stackItemType NewItem, bool& Success)
    • void Pop(bool& Success)
    • void Pop(stackItemType& StackTop, bool& Success)
    • void GetStackTop(stackItemType& StackTop, bool& Success)
  
  
  
• Applications of the stack data type
  • Evaluating postfix expressions
  • "Towers of Hanoi" puzzle program
  • depth-first search
  
  
  
• Implementations of the stack data type
  • array-based implementation
  • pointer-based implementation
  • "as-a-list" implementations
  
  
  
• Pro's and Con's of different implementations of the stack ADT.
  • array-based implementation
    • PRO: simple code
    • PRO: all operations are O(1) (compare with "list classes")
    • CON: static allocation
  • pointer-based implementation
    • PRO: dynamic memory allocation
    • PRO: most operations are O(1) (compare with "list classes")
    • CON: destructor is O(N)
    • CON: extra memory required for each element.
  • "as-a-list" implementations
    • PRO: extremely easy to program
    • PRO: if done a certain way, can be as efficient as coding "from scratch."
    • PRO: can be done with an array-based list or with a pointer-based list.
    • CON: There is extra function-call overhead.
    • CON: can be very inefficient if not done carefully -- the example code is inefficient if the list has the array implementation, and is efficient if the list has the linked implementation.