jzbakos jzbakos - 1 month ago 7
Java Question

How to increase efficiency by using for loops?

I am a beginner java programmer and I am making a simple TicTacToe game using 2D arrays and these are my if statements to check if player 1, or player 2 has won. I believe that this can be simplified by using for loop(s) however I do not understand how to use that method.

if ((grid[0][0] == 1 && grid[0][1] == 1 && grid[0][2] == 1)
|| (grid[1][0] == 1 && grid[1][1] == 1 && grid[1][2] == 1)
|| (grid[2][0] == 1 && grid[2][1] == 1 && grid[2][2] == 1)
|| (grid[0][0] == 1 && grid[1][1] == 1 && grid[2][2] == 1)
|| (grid[0][2] == 1 && grid[1][1] == 1 && grid[2][0] == 1)
|| (grid[0][0] == 1 && grid[1][0] == 1 && grid[2][0] == 1)
|| (grid[0][1] == 1 && grid[1][1] == 1 && grid[2][1] == 1)
|| (grid[0][2] == 1 && grid[1][2] == 1 && grid[2][2] == 1)
&& won == false) {
title.setText("X wins!");
won = true;
} else if ((grid[0][0] == 2 && grid[0][1] == 2 && grid[0][2] == 2)
|| (grid[1][0] == 2 && grid[1][1] == 2 && grid[1][2] == 2)
|| (grid[2][0] == 2 && grid[2][1] == 2 && grid[2][2] == 2)
|| (grid[0][0] == 2 && grid[1][1] == 2 && grid[2][2] == 2)
|| (grid[0][2] == 2 && grid[1][1] == 2 && grid[2][0] == 2)
|| (grid[0][0] == 2 && grid[1][0] == 2 && grid[2][0] == 2)
|| (grid[0][1] == 2 && grid[1][1] == 2 && grid[2][1] == 2)
|| (grid[0][2] == 2 && grid[1][2] == 2 && grid[2][2] == 2)
&& won == false) {
title.setText("O wins!");
won = true;
}


Below is the modified code that uses far less if statments and conditions.

public static boolean hasWon(int[][] grid) {
for (int a = 1; a <= 2; a++) {
for (int b = 0; b < grid.length; b++) {
// Checking for win in horizontal, then vertical, then diagonal
if (grid[b][0] == a && grid[b][1] == a && grid[b][2] == a) {
won = true;
} else if (grid[0][b] == a && grid[1][b] == a && grid[2][b] == a) {
won = true;
} else if ((grid[0][0] == a && grid[1][1] == a && grid[2][2] == a
|| (grid[0][2] == a && grid[1][1] == a && grid[2][0] == a))) {
won = true;
}
}
}
}

Answer

In order to help you reach a solution on your own I'll give you some hints for now.

Hint #1: Think about what it means to win. A player must get 3 of their tokens in a row - horizontal, vertical, or diagonal. Think about how that can be represented in your program.

Hint #2: Think about how you can break the problem into smaller more manageable pieces. Think about what each winning scenario has in common and separate that logic into a method that you can call multiple times.

Hint #3: Consider what makes each winning scenario unique and how you might use your grid to produce a representation of the spaces you want to examine that is easier to check for a win.

If you're not sure about how for loops work or other aspects of the Java Language you can find tutorials on Oracle's site

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