Challenges

Remember the rules for this are

• Try to use only the information given up to this point in this book.
• Try not to give up until you've given it a solid attempt

Challenge 1.

Initialize 10x10 2D array of ints by size. Print every element of this new 2D array.

Will any elements of the outermost array be null? Write down your guess before making the program.

void main() {
    int[][] xs = /* CODE HERE */
    // CODE HERE
}

Challenge 2.

Print out every character in the 2D array of chars. After each row print a new line.

void main() {
    char[][] picture = new char[][] {
        new char[] { ' ', ' ', ' ', ' ' },
        new char[] { ' ', '*', '*', ' ' },
        new char[] { '\\', ' ', ' ', '/' },
        new char[] { ' ', '-', '-', ' ' }
    };

    // CODE HERE
}

Challenge 3.

"Draw" a smiley face on the "canvas" provided by a 5x5 2D char array.

Use similar code as the previous challenge to print it out.

void main() {
    final char[][] picture = new char[5][5];

    // CODE HERE
}

Challenge 4.

Write a method named winner. It should take in a 2-dimensional array of Strings where each character is either X, O, or an empty string. This 2D array represents a game of Tic-Tac-Toe.

If there is a winner of the Tic-Tac-Toe game, it should return X or O depending on who the winner is. It should return null if nobody won or the game is a tie.

String winner(String[][] ticTacToe) {
    // CODE HERE
}

void main() {
    var winnerA = winner(new String[][] {
        new String[] { "X", "X", "" },
        new String[] { "O", "", "" },
        new String[] { "O", "", "" }
    });

    IO.println(winnerA);

    var winnerB = winner(new String[][] {
        new String[] { "X", "X", "X" },
        new String[] { "O", "O", "X" },
        new String[] { "O", "", "O" }
    });

    IO.println(winnerB);

    var winnerC = winner(new String[][] {
        new String[] { "O", "X", "O" },
        new String[] { "O", "O", "X" },
        new String[] { "O", "X", "O" }
    });

    IO.println(winnerC);
}