Question

public class StackTest
{
    public static void main(String[] args)
    {
        StackX theStack = new StackX(10);  // make new stack
        theStack.push(20);               // push items onto stack
        theStack.push(30);
        theStack.push(40);
        theStack.push(40);
        theStack.push(60);
        theStack.push(80);

        theStack.showStack();

        System.out.println("removeDownTo(40)");
        theStack.removeDownTo(40);

        theStack.showStack();

    }  // end main()
}

public class QueueTest
{
   public static void main(String[] args)
      {
      Queue theQueue = new Queue(20);  // queue holds 5 items

      theQueue.insert(10);            // insert 4 items
      theQueue.insert(20);
      theQueue.insert(30);
      theQueue.insert(40);

      theQueue.showQueue();
      
      System.out.println("Removing 3 items");
      theQueue.remove();              // remove 3 items
      theQueue.remove();              //    (10, 20, 30)
      theQueue.remove();
      
      theQueue.showQueue();

      System.out.println("Inserting 4 more items");
      theQueue.insert(50);            // insert 4 more items
      theQueue.insert(60);            //    (wraps around)
      theQueue.insert(70);
      theQueue.insert(80);
      theQueue.showQueue();

      System.out.println("Calling removeSecond()");
      long second = theQueue.removeSecond();
      theQueue.showQueue();

      }  // end main()
   }  

Attached Files:

• QueueTest.java (942 B)
• StackTest.java (507 B)

You may not use the java.util.Stack class.
You may not use the java.util.Queue class.

Ex1: Write a program that converts decimal to binary using a stack.

StackX class:
Ex2: Write method showStack(): It displays the contents of the stack starting with the first inserted element to the last. The stack would contain the same elements after showStack(). . If for example if to an empty stackx we push(20) then push(30) showStack() would print 20 30

Ex3: Write a method public static void removeDownTo (long n): It pops all values off the stack down to but not including the first element it sees that is equal to the second parameter. If none are equal, leave the stack empty.

Attach your StackX.java. I will use StackTest.java to test the above methods.

Queue class:
Ex4: Write method showQueue() to display the contents of the queue from first to last. The queue would contain the same elements after showQueue().

Ex5: Write a method public static Object removeSecond (): It removes and returns the element just behind the front element. Precondition: The queue has at least two elements.

Attach your Queue.java. I will use QueueTest.java to test the above methods.

Answer 1

Answer :2.,3

package stackOperations;
import java.util.Stack;

public class StackX {

   int st_elements[] = new int[10];
   int tos;

   StackX() {
       tos = -1; // indicate it's empty
   }

   public void push(int item) // for inserting element into stack in stack order
   {
       if (tos == 10) {
           System.out.println("stack is full");
           return;
       } else {
           st_elements[++tos] = item;
       }
   }

   public boolean empty_stack() // check that stack is empty or not
   {
       if (tos == -1)
           return true;
       else
           return false;
   }

   public int pop() // for retrieving element from stack
   {
       if (tos < 0) {
           System.out.println("stack underflow");
           return 0;
       } else
           return st_elements[tos--];
   }

   public boolean isEmpty() {
       return tos == -1;
   }

   public void showStack() // for printing the stack contains
   {
       int temp = 0;

       if (!empty_stack()) {
           temp = pop();
           System.out.println(temp);
           showStack();
       }
       push(temp);
   }

   public long peek() {
       return st_elements[tos];
   }

   static void removeDownTo(final StackX stack, final long downTo) {
       while (!stack.isEmpty()) {
           if (stack.peek() == downTo) {
               return;
           }

       }
   }
}