StackTrack.java

// (c) Roxy the Programming Fox

package stackLaboratory;
import java.util.*;

public class StackTrack {
    //attribs
    private Stack <Integer> mainStack;
    private Stack <Integer> nextMaxInStack;

    //constructors
    public StackTrack()
    {
        this.mainStack = new Stack<Integer>();
        this.nextMaxInStack = new Stack<Integer>();
    }

    //muttons
    public Stack<Integer> getMainStack() {
        return mainStack;
    }
    public void setMainStack(Stack<Integer> mainStack) {
        this.mainStack = mainStack;
    }
    public Stack<Integer> getnextMaxInStack() {
        return nextMaxInStack;
    }
    public void setnextMaxInStack(Stack<Integer> nextMaxInStack) {
        this.nextMaxInStack = nextMaxInStack;
    }

    //logicals
    /*  1. push to stack
     *  2. pop from stack
     *  3. peek from stack
     */
    public void push(int i)
    {
        this.mainStack.push(i);
        /* [if] first token,
         * -> first token is maximum (since it's the only token)
         *
         * [else, if] token > current maximum
         * -> push current token to nextMaxInStack
         *
         * [else] (token < or == current maximum)
         * -> push nextMaxInStack.peek() to nextMaxInStack
         */
        if (this.mainStack.size() == 1) {
            this.nextMaxInStack.push(i);
        }
        else if (i > this.nextMaxInStack.peek()){
            this.nextMaxInStack.push(i);
        }
        else {
            this.nextMaxInStack.push(this.nextMaxInStack.peek());
        }
    }

    public void pop()
    {
        Integer[] returnArray = {this.mainStack.pop(), this.nextMaxInStack.pop()};

        print(returnArray);
    }

    public void peek()
    {
        Integer[] returnArray = {this.mainStack.peek(), this.nextMaxInStack.peek()};

        print(returnArray);
    }

    public int nextLocalMaximum()
    {
        return this.nextMaxInStack.peek();
    }

    //print functions
    private void print(Integer[] n)
    {
        System.out.println(n[0] + "\t| " + n[1]);
    }

    public void popAll()
    {
        System.out.println("Current\t| Next");
        while(!this.mainStack.isEmpty())
            this.pop();
    }

    //hasNext
    public boolean hasNext()
    {
        if (!this.mainStack.isEmpty())
            return true;
        else return false;
    }


    //---main function---//
    //rand for generating stack
    static Random RAND = new Random();
    public static void main (String args[])
    {
        //initialize
        StackTrack st = new StackTrack();

        //put values (generate 10)
        for (int i = 0 ; i < 10 ; i++)
            st.push(RAND.nextInt(100));

        //pop values
        st.popAll();
    }
}

/* ---SAMPLE OUTPUT--- /
 * Current  | Next
 * 70       | 98
 * 21       | 98
 * 66       | 98
 * 87       | 98
 * 98       | 98
 * 33       | 45
 * 45       | 45
 * 32       | 32
 * 18       | 24
 * 24       | 24
 * ---SAMPLE OUTPUT--- */