Question

I currently have the following code below and I want to update the specific place in the 2D array with an X and then re-print the board. I am currently stuck where I need to update the object in the array to an X but I keep getting:

Type mismatch: cannot convert from String to Ship

What am I doing wrong? I have already placed all the objects on the board.

public void updateBoard(int row, int column, Ocean ocean){
    //get ship array
    Ship[][] sea = ocean.getShipArray();
    //mark the x/y co-ordinate with X 
    sea[row][column] = "X"; // PROBLEM  
    // print the board
}

I have included the Ship Class

public abstract class Ship {
// TODO add appropriate comments
@Getter
private int size;
private String type;
private String shortForm;

// TODO add appropriate comments
@Getter
@Setter(AccessLevel.PACKAGE)
private int bowRow;
@Getter
@Setter(AccessLevel.PACKAGE)
private int bowColumn;
@Getter
@Setter(AccessLevel.PACKAGE)
private boolean horizontal;

/**
 * An array of boolean which indicates whether that part of the ship has
 * been hit. This is initialised by the appropriate sub-class. Battleships
 * use all 4 locations; cruisers use the first 3; destroyers 2; submarines
 * 1; and "empty sea" 1.
 */
protected boolean[] hit;


/**
 * clears the hit array indicating whether that part of the "Ship" has been
 * hit
 */
protected Ship(int size, String type, String shortForm) {
    this.size = size;
    this.setType(type);
    this.shortForm = shortForm;
    hit = new boolean[size];
    for (int i = 0; i < hit.length; i++)
        hit[i] = false;
}

/**
 * Checks that ship of this size will not overlap another ship, or touch
 * another ship (vertically, horizontally, or diagonally) and that ship will
 * not "stick out" beyond the array.
 * 
 * @param row
 *            that will contain the bow
 * @param column
 *            that will contain the bow
 * @param horizontal = true if horizontal
 * @param ocean
 * @return true if it is okay to put a ship of this size with its bow in
 *         this location, with the given orientation.
 */
public boolean okToPlaceShipAt(int row, int column, boolean horizontal,
        Ocean ocean) {
    // Try to catch exception error if ship goes past board
    try{
        Ship ships[][] = ocean.getShipArray();

        for (int i = 0; i < getSize(); i++){
        if (!(ships[row][column] instanceof EmptySea)){ 
        //  System.out.println("Cant Print here + " + row + column + getSize());
                return false;
        }else{
            if (horizontal) {
                column++; 
            } else {
                row++;  
            }
        //  System.out.print(ships[row][column]);

            }
    //  System.out.println(" ");

        }
        return true;
    }
    catch(Exception err){
    //  System.out.println("OMG an error");
        return false;
    } 



}

/**
 * "places" the ship in the ocean, assigning values to the bowRow,
 * bowColumn, and horizontal. Places a reference to the ship in the ships
 * array in the Ocean object.
 * 
 * @param row
 *            to contain the bow
 * @param column
 *            to contain the bow
 * @param horizontal
 * @param ocean
 */
public void placeShipAt(int row, int column, boolean horizontal, Ocean ocean) {

    this.setBowRow(row);
    this.setBowColumn(column);
    this.setHorizontal(horizontal);

    Ship ships[][] = ocean.getShipArray();

    for (int i = 0; i < getSize(); i++) {
        // set position in array to contain the ship
        ships[row][column] = this;
        if (horizontal) {
            column++;
        } else {
            row++;
        }
    }
}

private int getSize() {
    // TODO Auto-generated method stub
    return size;
}

private void setHorizontal(boolean horizontal2) {
    // TODO Auto-generated method stub
    horizontal = horizontal2;
}

private void setBowColumn(int column) {
    // TODO Auto-generated method stub
    bowColumn = column;
}

private void setBowRow(int row) {
    // TODO Auto-generated method stub
    bowRow = row;
}

/**
 * If this ship has been hit, marks that part of the ship as "hit"
 * 
 * @param row
 *            User's supplied row shot
 * @param column
 *            User's supplied column shot
 * @return true if ship is hit, false otherwise
 */
public boolean shootAt(int row, int column) {
    if ((isHorizontal() && (row != getBowRow()))
            || (!isHorizontal() && (column != getBowColumn())))
        return false; // it's not a hit

    // it's a hit. Work out offset & set that position in hit array to true
    hit[(row - getBowRow() + column - getBowColumn())] = true;

            return true;
}

private int getBowRow() {
    // TODO Auto-generated method stub
    return bowRow;
}

private int getBowColumn() {
    // TODO Auto-generated method stub
    return bowColumn;
}

private boolean isHorizontal() {
    // TODO Auto-generated method stub
    return false;
}

/**
 * checks whether this ship is sunk - using the hit array
 * 
 * @return true if every part of the ship has been hit, false otherwise.
 */
public boolean isSunk() {

    for (boolean b : hit)
        if (!b)
            return false;

    return true;
}


/**
 * @return a single character String to use in Ocean's print method
 */
@Override
public String toString() {
    return shortForm;
}

public String getType() {
    return type;
}

public void setType(String type) {
    this.type = type;
}
public String setHit(String hit){
    return hit;
}

}

It is a bit long.
Below is a sample of one if the ships that extends Ship, the Submarine class. All the others are exactly the same except for their sizes.

/*
 * A Battleship class which extends ship
 * Four Submarines in the game Length 1
 */
package Battleships;
public class Submarine extends Ship {
    private final static int SIZE = 1;
    /**
     * sets the length & clears the hit array
     */
    public Submarine() {
        super(SIZE, "Submarine", "S");
    }
}

Answer 1

sea is a Ship[][], "X" is a String. You can’t place a String in a variable that holds Ship.

Edit:

Since you’re trying to shoot at a ship, rather than place a new ship, I suspect what you actually need is to use the following function from ship…

public boolean shootAt(int row, int column).

From the code for Ship, I’m guessing what you actually need to do is…

sea[row][column].shootAt(row,column);