Lecture Objectives for Stack Lecture

KNOW:

• That a stack is a LIFO (last-in-first-out) data structure
• That a stack is a useful data structure to use when items need to be processed in reverse order
• What information is stored in a stack frame (for function calls)
• That when a function is called, a stack frame is pushed on the runtime stack
• That when a function returns, a stack frame is popped off the runtime stack

BE ABLE TO:

• implement the stack operations (push, pop, isEmpty) using a linked list
• explain how the runtime stack is affected as a program makes function calls

Sample Exam Question:

Implement a function that satisfies the following pre- and post-conditions. You may assume that struct listNode is defined as

struct listNode{
   int data;
   struct listNode *next;
};


// PRE:  top is a pointer to a pointer that points to the top item in
//       a non-empty stack
// POST: the function returns the top item of the stack, and the
//       item has been popped off the stack
int pop (struct listNode **top);