1. Part-B1 Stacks

11. Array-based Stack in Java public class ArrayStack implements Stack { // holds the stack elements private Object S[ ]; // index to top element private int top = -1; // constructor public ArrayStack(int capacity) { S = new Object[capacity]); }

12. Array-based Stack in Java public Object pop() throws EmptyStackException { if isEmpty() throw new EmptyStackException (“ Empty stack: cannot pop ”); Object temp = S[top]; // facilitates garbage collection S[top] = null ; top = top – 1; return temp; } public int size() { return (top + 1);

13. Array-based Stack in Java public boolean isEmpty() { return (top < 0); } public void push(Object obj) throws FullStackException { if (size() == capacity) throw new FullStackException(&quot;Stack overflow.&quot;); S[++top] = obj; } public Object top() throws EmptyStackException { if (isEmpty()) throw new EmptyStackException(&quot;Stack is empty.&quot;); return S[top]; }