battleship/Ship.java

import java.util.Arrays;
public class Ship{
   public static final int X = 0;
   public static final int Y = 1;
   private boolean vertical;
   private int[] start;
   private int[] end;
   private int length;

   public Ship(int[] start,int[] end){
      this.start = start;
      this.end = end;
      this.correctSE();
      int cord;
      if (this.vertical) {
         cord = Y;
      }
      else {
         cord = X;
      }

      this.length = this.end[cord] - this.start[cord]+1;
   }

   public static int randint(int a, int b){
      int rand_dist = (int) (Math.random() * (double) (b + 1 - a));
      return rand_dist + a;
   }

   // creates new random ship
   public static Ship randomShip(int[] start, int[] end,int length, boolean vert) {

      int[] s_start = new int[2];
      s_start[X] = randint(start[X],end[X]);
      s_start[Y] = randint(start[Y],end[Y]);
      int[] s_end = s_start.clone();

      int cord;

      // what direction do we want this pointing?
      if (vert){
         cord = Y;
      }
      else {
         cord = X;
      }

      // check if out of bounds only one way, because if it doesn't work that way it SHOULD work the other way
      if (s_start[cord] + length-1 < end[cord]) {
         s_end[cord] += length-1;
      }
      else {
         s_end[cord] -= length-1;
      }

      return new Ship(s_start,s_end);
   }
   public int getLength() {
      return this.length;
   }
   public int[] getStart() {
      return this.start;
   }
   public int[] getEnd() {
      return this.end;
   }

   // ensures start and end are in the right place
   private void correctSE(){
      int cord;
      this.vertical = this.start[X] == this.end[X];
      if (this.vertical) {
         cord = Y;
      }
      else {
         cord = X;
      }

      int[] third_point;
      if (start[cord] > end[cord]){

         third_point = this.start;
         this.start = this.end;
         this.end = third_point;

      }
   }

   private void rotate(int[] point){

      // one point is tacked to the board and the other is moved around
      int[] stationary_point;
      int[] moving_point;

      // either the start or end will be stationary
      if (Arrays.equals(this.start,point)) {
         moving_point = this.end;
         stationary_point = this.start;
      }

      else {
         moving_point = this.start;
         stationary_point = this.end;
      }

      // get the new coordinates
      int new_x = stationary_point[X] + stationary_point[Y] - moving_point[Y];
      int new_y = moving_point[X] + stationary_point[Y] - stationary_point[X];

      // set them
      moving_point[X] = new_x;
      moving_point[Y] = new_y;
   }

   public void rotate(int[] point, int n){
      for (int i = 0; i < n; i++){
         this.rotate(point);
      }
      this.correctSE();
   }

   public boolean isVertical() {
      return this.vertical;
   }

   public boolean isInside(int[] start, int[] end){
      return this.start[X] >= start[X] && this.end[X] <= end[X] &&
      this.start[Y] >= start[Y] && this.end[Y] <= end[Y];
   }

   public boolean isIntersecting(Ship other){
      boolean cond1;
      boolean cond2;
      boolean cond3;
      int cord1;
      int cord2;
      // <necessary bit, ensures algorithm works both when other is oriented horizontally or vertically>
      if (other.vertical) {
         cord1 = X;
         cord2 = Y;
      }
      else {
         cord1 = Y;
         cord2 = X;
      }
      // </necessary bit>

      int t_s1 = this.start[cord1];
      int t_e1 = this.end[cord1];
      int o_s1 = other.start[cord1];
      int o_e1 = other.end[cord1];

      int t_s2 = this.start[cord2];
      int t_e2 = this.end[cord2];
      int o_s2 = other.start[cord2];
      int o_e2 = other.end[cord2];

      // lines are parallel
      if (this.vertical == other.vertical) {
         // overlaps
         cond1 = t_s2 == o_s2;

         // intersects
         cond2 = o_e1 >= t_s1;
         cond3 = t_e1 >= o_s1;

         return cond1 && (cond2 || cond3);
      }

      // lines are perpendicular
      else{

         // other in range of this with respect to axis cord1
         cond1 = (t_s1 >= o_s1) && (t_e1 <= o_e1);
         // this in range of other with respect to axis cord2
         cond2 = (o_s2 >= t_s2) && (o_e2 <= t_e2);
         return cond1 && cond2;
      }
   }

   public void print() {
      System.out.println("Start: " + "(" + this.start[X] + ", " + this.start[Y] + ")");
      System.out.println("End: " + "(" + this.end[X] + ", " + this.end[Y] + ")");
   }

   public void placeOnBoard(int[][] board){
      this.correctSE();
      int x_col = this.start[X];
      int y_col = this.start[Y];
      int c;
      if (this.vertical){
         for (c = this.start[Y];c <= this.end[Y];c++){
            System.out.println(c);
            board[c][x_col] = this.length;
         }
      }
      else {
         for (c = this.start[X];c <= this.end[X];c++){
            board[y_col][c] = this.length;
         }
      }
   }
}