Thread: Read ASCII art map and store the information in 2D array (int[][] or char[][])

See post #18. Option 2 is probably the simplest.

Cross posted here.

Hi, I've nearly finished everything now, and it wouldn't have been possible without your advice, so thanks!

One last question. I have to make it so entering "LOOK" will reply with a 5x5 grid of what is surrounding the player. I've done it using this code:

System.out.print(Map.matrix[playerX-2][playerY-2]);
			System.out.print(Map.matrix[playerX-2][playerY-1]);
			System.out.print(Map.matrix[playerX-2][playerY]);
			System.out.print(Map.matrix[playerX-2][playerY+2]);
			System.out.print(Map.matrix[playerX-2][playerY+2]);
			System.out.println("\n");
			System.out.print(Map.matrix[playerX-1][playerY-2]);
			System.out.print(Map.matrix[playerX-1][playerY-1]);
			System.out.print(Map.matrix[playerX-1][playerY]);
			System.out.print(Map.matrix[playerX-1][playerY+1]);
			System.out.print(Map.matrix[playerX-1][playerY+2]);
			System.out.println("\n");
			System.out.print(Map.matrix[playerX][playerY-2]);
			System.out.print(Map.matrix[playerX][playerY-1]);
			System.out.print(Map.matrix[playerX][playerY]);
			System.out.print(Map.matrix[playerX][playerY+1]);
			System.out.print(Map.matrix[playerX][playerY+2]);
			System.out.println("\n");
			System.out.print(Map.matrix[playerX+1][playerY-2]);
			System.out.print(Map.matrix[playerX+1][playerY-1]);
			System.out.print(Map.matrix[playerX+1][playerY]);
			System.out.print(Map.matrix[playerX+1][playerY+1]);
			System.out.print(Map.matrix[playerX+1][playerY+2]);
			System.out.println("\n");
			System.out.print(Map.matrix[playerX+2][playerY-2]);
			System.out.print(Map.matrix[playerX+2][playerY-1]);
			System.out.print(Map.matrix[playerX+2][playerY]);
			System.out.print(Map.matrix[playerX+2][playerY+1]);
			System.out.print(Map.matrix[playerX+2][playerY+2]);

Which works fine, unless a player is in a corner or against the wall of the map because then the player coordinate -2 leads to it trying to find something in the array that doesn't exist. I want to make it so if that happens it prints a "?" but I can't figure out how. The error I get is:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1

Thanks again!



EDIT:
Just had a brainwave - I did it using try and catch statements and it seems to be working perfectly!

I think you should stop at the edge of the playing field and NOT print a status for those areas of the playing field that don't exist. That would be easy enough to do with an 'if' statement.

However, if you insist on that approach, then enlarge your array so that there's a 2-column buffer on each side and a 2-row buffer across the top and bottom. The buffer area will not be involved in play but will give you the option to present '?' or whatever you'd like to show the 5x5 area.

--- Update ---

I think you should stop at the edge of the playing field and NOT print a status for those areas of the playing field that don't exist. That would be easy enough to do with an 'if' statement.

However, if you insist on that approach, then enlarge your array so that there's a 2-column buffer on each side and a 2-row buffer across the top and bottom. The buffer area will not be involved in play but will give you the option to present '?' or whatever you'd like to show the 5x5 area.

Hi, following on from my last question kind of, I'm trying to use a for loop to print out the 2d array that is around it. I'm trying to do this my creating a new 2d array of these coordinates but I'm having some trouble. Here's my code so far, but I don't know exactly how to do what I want to:

		char[][] theLookMatrix = new char[5][5];
 
 
		for (int i=-2; i<3; i++) {
		     for (int j=-2; j<3; j++)
		        theLookMatrix[][] =  Map.matrix[playerX+i][playerY+j]);
		        System.out.print(" ");
			    System.out.println("");
		        }

But there's an error on the line:

theLookMatrix[][] =  Map.matrix[playerX+i][playerY+j]);

Please can you help me fix it, thanks!

What's the error?

Originally Posted by GregBrannon

What's the error?

There isn't a runtime error as I can't run it. But it wants me to change - char theLookMatrix[][] to just char theLookMatrix. If I do this then there are still more errors.

In the line with the error, this term:

Map.matrix[playerX+i][playerY+j]

is one element of the matrix[][] which must be a char. You can't assign a single char to theLookMatrix[][] as that line is trying to do.

You're trying to translate a 5x5 portion of matrix[][] to theLookMatrix[][], such that

theLookMatrix[0][0] = matrix[x][y]

where x, y are the coordinates of the upper left corner of the desired 5x5 area. To generalize:

theLookMatrix[i][j] = matrix[x + i][y + j]

where i and j range from 0 through 4.

Sorry, I don't understand why I can't use Map.matrix[playerX+i][playerY+j]. I thought I would need to use the player's X and Y coordinates to print the 5x5 of what is around the player. I'll show you what I mean with the maps. Here is a full map:

# # # # # # # # # # # # # # # # # # # 
# . . . . . . . . . . . G . . . . . # 
# . . . . . . G . . . . . . G . E . # 
# . . . . . . G . . . . G . . . . . # 
# . . E . . . . G . G P . G . . . . # 
# . . . . . . . . . . G . . . . . . # 
# . . . . . . G . . . . . . . G G . # 
# . . . . G . . . . . . . . G . . . # 
# # # # # # # # # # # # # # # # # # #

And here is what I want the code about to look, a 5 by 5 grid with the player P at the centre.

.....
...G.
.GP.G
..G..
.....

Thanks!

I didn't suggest you couldn't use anything. You must have misread. I gave you a general approach that you can use to fit your specifics. Try rereading more slowly for comprehension.

This would be a great time to write a method that accepts a char matrix and prints it out in the desired form. You could use it for the full game field, for the 5x5 view, and any other time you needed it. Since you're already doing it for the full game field, you can easily generalize it to a method and use it for the 5x5 view.