Please help.

// --------------------------------------------------------

// DO NOT EDIT ANYTHING BELOW THIS LINE

// --------------------------------------------------------

/**

* Interface for an abacus for the AbacusGUI to use.

*/

public interface Abacus {

/**

* Gets the number base of the abacus. This base

* will never be an odd number and never be less

* than 2.

*

* @return the number base of the abacus

*/

public int getBase();

/**

* Returns the number of places (bead columns) the

* abacus is using to represent the number. This

* will never be less than one.

*

* @return the number of places in use

*/

public int getNumPlaces();

/**

* Gets the number of beads in the top area of the

* abacus which are in-use for a given place. (The

* number of beads in the top which are pushed down

* to the center.)

*

* @param place the beads column of interest (0 is the right-most place)

* @return the number of beads currently in use

* @throws IndexOutOfBoundsException if the place requested is not in use

*/

public int getBeadsTop(int place);

/**

* Gets the number of beads in the bottom area of the

* abacus which are in-use for a given place. (The

* number of beads in the bottom which are pushed up

* to the center.)

*

* @param place the beads column of interest (0 is the right-most place)

* @return the number of beads currently in use

* @throws IndexOutOfBoundsException if the place requested is not in use

*/

public int getBeadsBottom(int place);

/**

* Adds the given string representation of a number to

* the current value of the abacus. The abacus is updated

* to this new position. It returns the steps to perform

* the add (snap shots of the abacus at each step). The

* abacus may be left in an "improper state" if the

* provided arguements are invalid.

*

*

A snapshot is required for each of the following steps:

*

*

• - the initial state

  *

• - the final state

  *

• - expansions (beads should not be moved, the abacus just

  * becomes bigger/smaller)

  *

• - exchanges (beads are exchanged in one step)

  *

• - movement of X beads up OR down (not both at the same time)

  * in ONE place on the bottom OR top of the abacus (not both

  * at the same time)

  *

*

* @param value the string representation of the value to add (e.g. "100" in base 10, or "1f" in base 16)

* @return the different positions the abacus was in (including the start and finish states)

* @throws NumberFormatException if string is not correct for the base

*/

public DynArr310 add(String value);

}

import java.util.Scanner;

/**

* A little GUI to help you interact with the abacus.

* Use with the command:

* java AbacusGUI

* or

* java AbacusGUI full

*/

public class AbacusGUI {

/**

* The main method that presents the GUI.

*

* @param args command line args (if first is "full" shows steps, otherwise ignored)

*/

public static void main(String[] args) {

boolean full = (args.length == 1 && args[0].equals("full"));

try (Scanner s = new Scanner(System.in)) {

Abacus a = null;

while(true) {

try {

System.out.print("Enter a base: ");

a = new MyAbacus(s.nextInt());

s.nextLine();

printAbacus(a);

break;

}

catch(RuntimeException e) {

System.out.println(e.toString());

}

}

while(true) {

System.out.print("What would you like to add? (Enter anything invalid to quit.) ");

if(full) {

fullPrintAdd(a, s.nextLine());

}

else {

a.add(s.nextLine());

printAbacus(a);

}

}

}

catch(Exception e) {

System.out.println("Goodbye!");

}

}

/**

* Adds the value to the abacus, then prints all the steps

* this is probably useful for debugging.

*

* @param a the abacus to add to

* @param value the value to add to the abacus

*/

public static void fullPrintAdd(Abacus a, String value) {

DynArr310 steps = a.add(value);

System.out.println("------------------------------");

System.out.println("- Starting State");

System.out.println("------------------------------");

printAbacus(steps.get(0));

System.out.println("------------------------------");

System.out.println("- Adding " + value);

System.out.println("------------------------------");

for(int i = 1; i < steps.size(); i++) {

printAbacus(steps.get(i));

}

System.out.println("------------------------------");

System.out.println("- Done");

System.out.println("------------------------------");

}

/**

* Prints a single abacus with amazing graphics.

*

* @param a the abacus to print

*/

public static void printAbacus(Abacus a) {

StringBuilder sb = new StringBuilder();

//build abacus structure

int bottomSize = a.getBase()/2;

int numPlaces = a.getNumPlaces();

int width = (numPlaces*4)+4;

//top

sb.append("/ ");

printRows(sb, numPlaces, "---"); //em-dashes

sb.append(" \\ ");

//top beads

for(int i = 0; i < 3; i++) {

sb.append("| ");

printRows(sb, numPlaces, " | "); //em-dashes

sb.append(" | ");

}

//middle

sb.append("| ");

printRows(sb, numPlaces, "---");

sb.append(" | ");

//bottom beads

for(int i = 0; i < (bottomSize)+2; i++) {

sb.append("| ");

printRows(sb, numPlaces, " | "); //em-dashes

sb.append(" | ");

}

//bottom

sb.append("\\ ");

printRows(sb, numPlaces, "---");

sb.append(" / ");

//put beads in place

for(int i = 0; i < numPlaces; i++) {

//top beads

int topBeads = a.getBeadsTop(i);

for(int j = 0; j < 3; j++) {

if(topBeads != j) {

int spot = calcSpotTop(i, width, 3-j);

sb.setCharAt(spot,'O');

}

}

int bottomBeads = a.getBeadsBottom(i);

for(int j = 0; j < bottomBeads; j++) {

int spot = calcSpotBottom(i, width, j);

sb.setCharAt(spot,'O');

}

for(int j = 0; j < bottomSize-bottomBeads; j++) {

int spot = calcSpotBottom(i, width, bottomSize-j+1);

sb.setCharAt(spot,'O');

}

}

System.out.println(sb.toString());

}

/**

* Calculaton for the placement of a single bead

* on the top.

*

* @param place the place (column) of the abacus (0 is rightmost)

* @param width the width of the ascii art

* @param num the bead position (1=top,2=middle,3=bottom)

* @return the index into the ascii art to draw the bead

*/

private static int calcSpotTop(int place, int width, int num) {

int spot = (width*num) + (width - ((place+1)*4) - 1);

return spot;

}

/**

* Calculaton for the placement of a single bead

* on the bottom.

*

* @param place the place (column) of the abacus (0 is rightmost)

* @param width the width of the ascii art

* @param num the bead position (1 to base/2, 1 is at the top)

* @return the index into the ascii art to draw the bead

*/

private static int calcSpotBottom(int place, int width, int num) {

int spot = (width*(num+5)) + (width - ((place+1)*4) - 1);

return spot;

}

// TO DO: add your implementation and JavaDocs

public class MyAbacus implements Abacus {

// ADD MORE PRIVATE MEMBERS HERE IF NEEDED!

// Remember: Using an array in this class = no credit on the project!

public MyAbacus(int base) {

// throws IllegalArgumentException if base is invalid

// remember: an abacus should always have at least one

// column!

}

public int getBase() {

// O(1)

return -1; //default return, make sure to remove/change

}

public int getNumPlaces() {

// O(1)

return -1; //default return, make sure to remove/change

}

public int getBeadsTop(int place) {

// O(1)

return -1; //default return, make sure to remove/change

}

public int getBeadsBottom(int place) {

// O(1)

return -1; //default return, make sure to remove/change

}

public boolean equals(MyAbacus m) {

// O(N) where N is the number of places currently

// in use by the abacus

return false; //default return, make sure to remove/change

}

public DynArr310 add(String value) {

// Hints:

// see: https://docs.oracle.com/javase/8/docs/api/java/lang/Integer.html#parseInt-java.lang.String-int-

// and: https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#charAt-int-

// Also... I personally found a recursive helper function really, really useful here...

// Important: each Abacus in the DynArr310 returned should

// be a copy of this abacus. If you just add this abacus over and over

// you'll just get the final abacus shown multiple times in the GUI.

return null; //default return, make sure to remove/change

}

// --------------------------------------------------------

// example testing code... edit this as much as you want!

// --------------------------------------------------------

public static void main(String[] args) {

//this is the sequence from the project description

Abacus a = new MyAbacus(10);

DynArr310 steps;

AbacusGUI.printAbacus(a);

AbacusGUI.fullPrintAdd(a, "36");

AbacusGUI.fullPrintAdd(a, "12");

AbacusGUI.fullPrintAdd(a, "2");

AbacusGUI.fullPrintAdd(a, "12");

AbacusGUI.fullPrintAdd(a, "10");

AbacusGUI.fullPrintAdd(a, "2");

AbacusGUI.fullPrintAdd(a, "68");

AbacusGUI.fullPrintAdd(a, "50");

AbacusGUI.fullPrintAdd(a, "10");

AbacusGUI.fullPrintAdd(a, "5");

AbacusGUI.fullPrintAdd(a, "3");

AbacusGUI.fullPrintAdd(a, "128");

AbacusGUI.fullPrintAdd(a, "3000000");

}

}

/**

* Prints a row of some pattern to the given StringBuilder.

*

* @param sb the builder to append to

* @param numPlaces the number of the sequence to add

* @param seq the sequence to repeat

*/

private static void printRows(StringBuilder sb, int numPlaces, String seq) {

for(int i = 0; i < numPlaces; i++) {

sb.append(seq);

if(i != numPlaces-1) sb.append(" ");

}

}

}