CODEWITHSUNDEEP
javastringboolean
Mark
Mark

Reputation: 25

either a rookie mistake, or misuse of .equals in java

So I'm making a TicTacToe-program, and I made a method for checking if there are 3 pieces in a row, to check if the game is over or not.

public boolean hasWon() {
    if (tictac[0][0].equals(tictac[1][0]) && tictac[0][0].equals(tictac[2][0]) && tictac[1][0].equals(tictac[2][0])) { //Vertical
        return false;
    } else if (tictac[0][1].equals(tictac[1][1]) && tictac[0][1].equals(tictac[2][1]) && tictac[1][1].equals(tictac[2][1])) { //Vertical
        return false;
    } else if (tictac[0][2].equals(tictac[1][2]) && tictac[0][2].equals(tictac[2][2]) && tictac[1][2].equals(tictac[2][2])) { //Vertical
        return false;

    } else if (tictac[0][0].equals(tictac[0][1]) && tictac[0][0].equals(tictac[0][2]) && tictac[0][1].equals(tictac[0][2])) { //Horizontal
        return false;
    } else if (tictac[1][0].equals(tictac[1][1]) && tictac[1][0].equals(tictac[1][2]) && tictac[1][1].equals(tictac[1][2])) { //Horizontal
        return false;
    } else if (tictac[2][0].equals(tictac[2][1]) && tictac[2][0].equals(tictac[2][2]) && tictac[2][1].equals(tictac[2][2])) { //Horizontal
        return false;

    } else if (tictac[0][0].equals(tictac[1][1]) && tictac[0][0].equals(tictac[2][2]) && tictac[1][1].equals(tictac[2][2])) { //Diagonal
        return false;
    } else if (tictac[0][2].equals(tictac[1][1]) && tictac[0][2].equals(tictac[2][0]) && tictac[1][1].equals(tictac[2][0])) { //Diagonal
        return false;

    } else {
        return true;
    }
}

The problem here is, with these conditions I figured if, say, all of the indexes "in a row" where f.ex. X, " X X X " it would be a win for the player X. However, my program calls for a winner if any kind of piece fill 3 in a row, f.ex. " X O X " would end the game, which obviously is wrong. Have I misunderstood .equals?

EDIT: after the wonderful feedback, is there a way that I can make the if-statements to ignore blank spaces (" ")?

Upvotes: 0

Views: 150

Answers (2)

Gangnus
Gangnus

Reputation: 24464

Your prog returns true if all three values on some line are the same. So, it won't return true on XOX. But would on OOO, XXX and SpaceSpaceSpace.

The first two are both OK, for if you check after a move, only the last mover could have three in a line and win. But three spaces are a problem. In every if you should check the first cell for not having space.

It is longer, but if you use the advice of @ajb, you'll even shorten the prog.

As for structuring, I would advice more simple way than that of @syrion. Make an array lines[5,3,2]. It has 5 lines, 3 cells for every line and 2 coords for every cell. And you can do the check in two inserted loops. It is not a Java way to do things, but you can take it as a first step. Or you could move immediately to a more readable structure - a list of 5 x lines= array of Cell = pair of coordinates. I don't know which one is more simple for you.

Upvotes: 0

asthasr
asthasr

Reputation: 9407

You should consider creating a class, Board. Have this class provide an interface that includes getLines. This should return a List<Line>. There are eight lines in a tic tac toe board: three horizontal, three vertical, two diagonal. Create a method isWin(String player, Line line). Return true or false based on whether the count of the player's marker in the cells of the line is three.

I would guess you can write the whole thing in the same amount of space as the horrible nested if with all its inscrutable && clauses, and the functioning will be obvious. (This is also good practice for encapsulation.)

Upvotes: 1

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