Stack (LIFO) [26]

Static Structure Diagram:

Collaboration Diagram:

$\bullet$ Stack is fixed size array, which only holds integers

$\bullet$ Stack maintains Last-In First-Out (LIFO) by incrementing/decrementing top

Stack: Java [27]

class Stack {

  public static void main(String args[]) {
    Stack s = new Stack();
    s.push(5); 
    s.push(1); 
    s.push(7); 
    while (!s.isEmpty()) 
      System.out.println(s.pop());
  }

  private static final int STACK_SIZE  = 100;
  private static final int EMPTY_TOS   = -1;
  private int top = EMPTY_TOS;
  int stack_array[] = new int[STACK_SIZE];

  public Stack () { }

  public boolean isEmpty() {
    return(top == EMPTY_TOS);
  }

  public boolean isFull() { 
    return(top == STACK_SIZE-1);
  }

  public void push(int i) {
    if (!isFull()) 
      stack_array[++top]= i;
  }

  public int pop() {
    if (isEmpty()) 
      return 0;
    else
      return(stack_array[top--]);
  }
}