CODEWITHSUNDEEP
javaobjectmultidimensional-array
tommy knocker
tommy knocker

Reputation: 371

Object Creation and putting them into a 2D array

i am having difficulty with 2D arrays and inserting objects that take 3 parameters (int x, int y, int cost) This is the beginning of a search algorithm and admittedly im off to a very poor start. I will paste the code below. I am receiving a compiling error when i try to run this code and i'm very sure it is simple but i cannot resolve it. The Map2 class i intend to use to implement the main bulk of the algorithms, such as sorting etc.

 import java.util.Arrays;


    public class Map2 {

        public static void main (String args[]){

         Points[][] grid = new Points[4][4];

         for(int i = 0; i < grid.length; i++){
             for(int j = 0; j < grid.length; j++){
                 grid[i][j] = new Points(i,j,1);
             }


         }
         System.out.print(Arrays.deepToString(grid));

    }
    }

This class is my object, it contains the movement cost from moving from one position to the next (the next step obviously would be to determine neighbors) and yes, this is part of trying to create a working A star algorithm.

 public class Points {
     int x;
     int y;
     int movement_cost;

    public  Points(int iX, int iY, int cost){
        x = iX;
       y = iY;
        movement_cost = cost;

    }

    public int getX(){
        return x;
    }
    public int getY(){
        return y;
    }
    public int getMovementCost(){
        return movement_cost;
    }
    public void setX(int x){
        this.x = x;
    }
    public void setY(int y){
        this.y = y;
    }
    public void setMovementCost(int cost){
        this.movement_cost = cost;
    }
    public String toString(){
        return ""+getX()+ ""+getY()+""+getMovementCost();
    }
}

This is the console read out after compiling (3 address spaces in memory)

    run:[[001, 011, 021, 031], [101, 111, 121, 131], 
[201, 211, 221, 231], [301, 311, 321, 331]]
BUILD SUCCESSFUL (total time: 2 seconds)

My hope here is simple, each object in the array will contain a reference of its coordinates in memory and contain a cost of movement, which would later be used to compare in order to determine the next best position (i will later implement things such as goal, start)

my question is: whats wrong with the code the way it is ?

I want to thank, in advance whomever responds as your responce will always be appreciated

CURRENT REVISION OF MY QUESTION V0.1: Wow well thanks for the quick responces, i have learned something new today ^^ that Arrays.deepToString(grid)); is an amasing tool i was not aware of, however i am still receiving a runtime error . Thank you once again for your replies and once again for any further responces :). The code above has been revised as recommended, but the runtime error still exists

Upvotes: 1

Views: 2345

Answers (1)

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 726479

There are several things that are wrong with your code:

  • Your nested loops assume that the array is square (you iterate both dimensions to grid.length),
  • You print the entire array after initializing each row, and
  • You print the array incorrectly (Java array do not print their content when passed to System.out.println)

The first item is OK if your matrix is indeed always square. The second item is easy to fix by moving the output outside of the second nested loop.

The third item is the hardest. It would be a good exercise to write a static method that takes your 2D array, and prints it out element-by-element with two nested loops. You can also use System.out.println(Arrays.deepToString(grid)); if you would rather use a system function.

Upvotes: 1

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