0. Here is a print2DArray method that will be useful for testing your work:

public static void print2DArray(String[][] arr) {
	System.out.print("[ ");
	for (int i = 0; i < arr.length; i++) {
		if (i != 0) System.out.print("  ");
		System.out.print("[");
		for (int j = 0; j < arr[0].length; j++) {
			System.out.print(arr[i][j]);
			if (j != arr[0].length - 1) {
				System.out.print(", ");
			}
		}
		System.out.print("]");
		System.out.println(i == arr.length - 1 ? " ]" : ",");
	}		
}

Copy and paste print2DArray into Eclipse and overload the method so it also works on 2D arrays of ints.

1. Write a method alternatingBoard that takes a 2D array of Strings as its inputs and works like this:

Given:

String[][] strs = new String[4][7];
alternatingBoard(strs);
print2DArray(strs);

then strs the output will be:

[ [ X, O, X, O, X, O, X ],
  [ O, X, O, X, O, X, O ],
  [ X, O, X, O, X, O, X ],
  [ O, X, O, X, O, X, O ] ]

2. Write the method neighbors that takes a 2D array of booleans as its input. It returns a 2D array of ints, where the int at position (row, col) in the array contains the number of neighbors of (row, col) that are true. A neighbor is defined to be a position that is adjacent either horizontally, vertically, or diagonally.

Examples:

boolean[][] grid = { { true, false, false},
                     { false, false, false },
                     { false, true, false } };

will print:

[ [0, 1, 0],
  [2, 2, 1],
  [1, 0, 1] ]

and

boolean[][] grid = { { false, false, false, false, false, true, false },
                     { false, false, true, false, false, false, false },
                     { false, true, false, true, false, false, false },
                     { false, false, true, false, false, false, true },
                     { false, false, false, false, true, false, false } };
print2DArray(neighbors(grid));

will print:

[ [0, 1, 1, 1, 1, 0, 1],
  [1, 2, 2, 2, 2, 1, 1],
  [1, 2, 4, 2, 1, 1, 1],
  [1, 2, 2, 3, 2, 2, 0],
  [0, 1, 1, 2, 0, 2, 1] ]