Tic Tac Toe

Let's build a terminal based Tic Tac Toe game in Go!

Setup

Create a folder named tictactoe in your go-academy directory. Then create a main.go inside it. We will put the game logic into a package named ttt. For now, just make an empty ttt folder inside tictactoe.

WORKSPACE/
    src/
        go-academy/
            tictactoe/
                main.go
                ttt/
                    ...

Object Oriented Programming in Go

Let's define what are entities that we need for a terminal based Tic Tac Toe game.

Game: This is a struct that keeps track of the turns, the players, and the board information.

Player: This is an interface that has the following methods.

GetMove(*board) (int, int, error)
Mark() string
Name() string

HumanPlayer and ComputerPlayer

board: This is an 3 by 3 array that keeps track of X and O marks, using _ to render empty space.

Quick Note

Private vs Public

Functions or variables with upper-cased name are exported from a package. If the functions or variables have lower-cased name, then program outside of the package cannot have reference to them. I chose to make board a private struct because user need not to care about the implementation and usage of game board.