Programming Forums > Application Development > Java

cwl157 · Apr 7th, 2005, 2:45 PM

I need to write a 2 deminsional array in java. I can display the array fine with all the initialized to 0 but how do i change the number of a specific coordinates
here is the array now:

(Toggle Plain Text)

public class Board
{
   
   public static void main(String args[])
   {
      int[][] ar = new int[10][10];
      Board.setBoard(ar);
   }
    
    
    public static void setBoard(int[][] ar)
    {
       for (int r=0; r<ar.length; r++)
       {
            for (int c=0; c<ar[r].length; c++)
            {
                System.out.print(" " + ar[r][c]);
            }
           System.out.println("");
      }
    }
}

Mjordan2nd · Apr 7th, 2005, 2:52 PM

Ok, so basically, right now your array looks something like this:

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 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 0 0
 0 0 0 0 0 0 0 0 0 0

Now, lets say, you wanted to change the value in the 5th row and 5th column to 5, you'd say something like this:

(Toggle Plain Text)

ar[4][4] = 5;

Now your array will look like this:

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  0 0 0 0 0 0 0 0 0 0
  0 0 0 0 0 0 0 0 0 0
  0 0 0 0 0 0 0 0 0 0
  0 0 0 0 0 0 0 0 0 0
  0 0 0 0 5 0 0 0 0 0
  0 0 0 0 0 0 0 0 0 0
  0 0 0 0 0 0 0 0 0 0
  0 0 0 0 0 0 0 0 0 0
  0 0 0 0 0 0 0 0 0 0
  0 0 0 0 0 0 0 0 0 0

Berto · Apr 8th, 2005, 2:41 AM

If that doesnt help draw the grid on a piece of paper, just think of it as coordiantes

(5,2) and so that would be myArray[5][2]

cwl157 · Apr 14th, 2005, 7:44 AM

so now how would i change the number in a random row and random column cause thats really what i need to do?

Infinite Recursion · Apr 14th, 2005, 10:22 AM

generate a random number within the bounds of your row index [R] and another one in the bounds of your column index [C]. Then make the assignment...

ar[R][C] = yourVal;

I wrote something like this in C++ for the "Game of Life" when i was in college.

You Like Java? · Apr 28th, 2005, 12:03 AM

(Toggle Plain Text)

public class LikeThis
{
   public static void main(String[] args)
   {
	 //example data
	 int[][] array = new int[5][10];
	 double value = 23.5;
 
	 /*
	 create the Random object with the
	 time in miliseconds as the seed
	 */
	 long seed = new Date().getTime();
	 Random randNumGen = new Radnom(seed);
 
	 //get the coordinates
	 int x = randNumGen.nextInt(5);
	 int y = randNumGen.nextInt(10);
 
	 //access and modify the array
	 array[x][y] = value;
   }
}

Apr 7th, 2005, 2:45 PM	#1
cwl157 Professional Programmer Join Date: Feb 2005 Posts: 333 Rep Power: 4	multi-demensional arrays I need to write a 2 deminsional array in java. I can display the array fine with all the initialized to 0 but how do i change the number of a specific coordinates here is the array now: (Toggle Plain Text) public class Board { public static void main(String args[]) { int[][] ar = new int[10][10]; Board.setBoard(ar); } public static void setBoard(int[][] ar) { for (int r=0; r<ar.length; r++) { for (int c=0; c<ar[r].length; c++) { System.out.print(" " + ar[r][c]); } System.out.println(""); } } } public class Board { public static void main(String args[]) { int[][] ar = new int[10][10]; Board.setBoard(ar); } public static void setBoard(int[][] ar) { for (int r=0; r<ar.length; r++) { for (int c=0; c<ar[r].length; c++) { System.out.print(" " + ar[r][c]); } System.out.println(""); } } }

Apr 7th, 2005, 2:52 PM	#2
Mjordan2nd The Supreme Ruler Join Date: May 2004 Location: Houston Posts: 1,476 Rep Power: 6	Ok, so basically, right now your array looks something like this: (Toggle Plain Text) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Now, lets say, you wanted to change the value in the 5th row and 5th column to 5, you'd say something like this: (Toggle Plain Text) ar[4][4] = 5; ar[4][4] = 5; Now your array will look like this: (Toggle Plain Text) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 __________________ "Every gun that is made, every warship launched, every rocket signifies, in the final sense, a theft from those who hunger and are not fed, from those who are cold and are not clothed. The world in arms is not spending money alone. It is spending the sweat of its laborers, the genius of its scientists, the hopes of its children." - Dwight D. Eisenhower

Apr 14th, 2005, 10:22 AM	#5
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,467 Rep Power: 8	generate a random number within the bounds of your row index [R] and another one in the bounds of your column index [C]. Then make the assignment... ar[R][C] = yourVal; I wrote something like this in C++ for the "Game of Life" when i was in college. __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Apr 28th, 2005, 12:03 AM	#6
You Like Java? Newbie Join Date: Mar 2005 Location: aboho.com (sn:eyvind) Posts: 20 Rep Power: 0	(Toggle Plain Text) public class LikeThis { public static void main(String[] args) { //example data int[][] array = new int[5][10]; double value = 23.5; /* create the Random object with the time in miliseconds as the seed / long seed = new Date().getTime(); Random randNumGen = new Radnom(seed); //get the coordinates int x = randNumGen.nextInt(5); int y = randNumGen.nextInt(10); //access and modify the array array[x][y] = value; } } public class LikeThis { public static void main(String[] args) { //example data int[][] array = new int[5][10]; double value = 23.5; / create the Random object with the time in miliseconds as the seed */ long seed = new Date().getTime(); Random randNumGen = new Radnom(seed); //get the coordinates int x = randNumGen.nextInt(5); int y = randNumGen.nextInt(10); //access and modify the array array[x][y] = value; } } __________________ If you need help with Java, you can go to javaforum.tk and get answers quickly. Programmer YouLikeJava = new JavaProgrammer("Eyvind"); YouLikeJava.printInfo(); YouLikeJava.setWeb("You Like Java?");

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Apr 8th, 2005, 2:41 AM	#3
Berto Programming Guru Join Date: Aug 2004 Posts: 1,022 Rep Power: 6	If that doesnt help draw the grid on a piece of paper, just think of it as coordiantes (5,2) and so that would be myArray[5][2]

Apr 14th, 2005, 7:44 AM	#4
cwl157 Professional Programmer Join Date: Feb 2005 Posts: 333 Rep Power: 4	so now how would i change the number in a random row and random column cause thats really what i need to do?

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Programming Forums > Application Development > Java

multi-demensional arrays