Revise the program below class to implement it using an array rather than an Arr

Question

Revise the program below class to implement it using an array rather than an ArrayList. You should check the array size before adding a new element to the stack. if the array is full, create a new array that doubles the current array size and copy the elements from the current array to the new array.

Program:

public class GenericStack<E> {
private java.util.ArrayList<E> list = new java.util.ArrayList<E>();

public int getSize() {
return list.size();
}

public E peek() {
return list.get(getSize() - 1);
}

public E push(E o) {
list.add(o);
return o;
}

public E pop() {
E o = list.get(getSize() - 1);
list.remove(getSize() - 1);
return o;
}

public boolean isEmpty() {
return list.isEmpty();
}
}

Explanation / Answer

Dear, /** Array Implementation of a stack. */ public class ArrayStack { private int [] s; // Holds stack elements private int top; // Stack top pointer /** Constructor. @param capacity The capacity of the stack. */ public ArrayStack (int capacity) { s = new int[capacity]; top = 0; } /** The empty method checks for an empty stack. @return true if stack is empty. */ public boolean empty() { return top == 0; } /** The push method pushes a value onto the stack. @param x The value to push onto the stack. @exception StackOverflowException When the stack is full. */ public void push(int x) { if (top == s.length) throw new StackOverFlowException(); else { s[top] = x; top ++; } } /** The pop method pops a value off the stack. @return The value popped. @exception EmptyStackException When the stack is empty. */ public int pop() { if (empty()) throw new EmptyStackException(); else { top--; return s[top]; } } /** The peek method returns the value at the top of the stack. @return value at top of the stack. @exception EmptyStackException When the stack is empty. */ int peek() { if (empty()) throw new EmptyStackException(); else { return s[top-1]; } } } /** This class demonstrates the use of the ArrayStack class. */ public class ArrayStackDemo { public static void main(String [] arg) { String str; // Use for output ArrayStack st = new ArrayStack(5); str = "Pushing 10 20 onto the stack."; System.out.println(str); st.push(10); st.push(20); str = "Value at top of the stack is "; System.out.println(str + st.peek()); str = "Popping and printing all values:"; System.out.println(str); while (!st.empty()) System.out.print(st.pop() + " "); } } Hope this will help you

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