2048

function twos()

    clc

    n = mainmenuprint();
    %Print main menu to ask user what to do

    switch n
        case 1
            %Play new game
            game(zeros(4,4))
        case 2
            %Play game loaded from file
            game(dbread())
        case 0
            %Quit
            clc
            clear
            return
    end

end

function c = mainmenuprint()
%This function displays the homescreen
%and asks the user what they want to do

    while 1
        clc

%Bask in the glory of my ASCII art skills.
%Jk. Generated at http://bigtext.org/

        fprintf('\n ____   ___  _  _    ___  ')
        fprintf('\n|___ \\ / _ \\| || |  ( _ ) ')
        fprintf('\n  __) | | | | || |_ / _ \\ ')
        fprintf('\n / __/| |_| |__   _| (_) |')
        fprintf('\n|_____|\\___/   |_|  \\___/ ')

        fprintf('\n\n-----Welcome to 2048!-----')

        fprintf('\n\n1. New game')
        fprintf('\n2. Load game from file')
        fprintf('\n0. Quit')

    %Takes user input. (It is taken as a string to make sure
    %invalid inputs (like letters) can be ignored)

        c = str2double(input('\n\nMake a choice(0, 1 or 2) and press Enter : ','s'));

        if ~ismember(c,0:2)
            continue
        end

        break

    end

end

function game(board)
%This function is the backbone of the game

%If the board has less than two full spaces for
%any reason, it assigns either a 2 or a 4 to two
%random spaces on the board

    if  sum(sum(board ~= 0))<2;
        a = [randperm(4,2)',randperm(4,2)'];
        b = 2.*randi(2,2,1);
        a(:,3) = b;
        board(a(1,1),a(1,2)) = a(1,3);
        board(a(2,1),a(2,2)) = a(2,3);
    end

    clc
    %Prints the board
    printboard(board)
    %Prints the menu
    c = printmenu();

    %A variable that may or may not be useful.
    %It was useful in earlier versions but I am too
    %afraid to take it away now.
    d = 'n';

    %While the board has empty spaces, or is deemed
    %playable by my lovely poss() function.
    while sum(sum(board ==0))>0 || poss(board)

        if strfind('wasd',c)
            %If the input was a direction, move the
            %move the board pieces in that direction
            [board,d] = movewhile(board,c);
        elseif c == 'l'
            %Save the current board to a file and
            %return to the main menu
            dbwrite(board)
            twos()
            return
        elseif c == 'p'
            %Return to the main menu
            twos()
            return
        else
            %If the user enters nothing, ask the
            %user for an input again and restart
            %the loop
            clc
            printboard(board)
            c = printmenu();
            continue
        end

        %This was useful in earlier versions. Now I'm
        %afraid it'll break the code if I remove it,
        %so it stays.
        if d ~= 'n'
            c = d;
            continue
        end

        clc

        printboard(board)
        c= printmenu();
    end

    %When the while loop is over, the user is informed
    %that the game is over and is returned to the main
    %menu.
    fprintf('\n Game Over. :(\n')
    pause(5)
    twos()
    return
end

function [board, d] = movewhile(board,k)
%Moves the board pieces in the desired direction.

%This is slightly different to how the original
%game works due to an oversight on my part.
%It is slightly harder to code my version
%anyway so I'll just go with saying
%that I took it as a challenge :)

%I only explained the case where the option is to move
%downwards (k == 's') because the rest are the same but with different
%variables changing.

%Makes a single-layer padding of NaN-variables
%around the board.
    d = 'n';
    first = board;
    g = NaN(6,6);
    g(2:5,2:5) = board;
    board = g;

    if k == 's'
        %down
        for r = 4:-1:2
            %Starts on the third row and moves upwards.
            for c = 2:5
                if board(r,c) ~= 0
                    %If the piece is non-zero
                    if board(r,c) == board(r+1,c)
                        %If the piece is the same as the one below it,
                        % nullify itself and double the piece below it
                        board(r+1,c) = board(r,c).*2;
                        board(r,c) = 0;
                    elseif board(r+1,c) == 0
                        %if the piece below it is empty
                        p = r;
                        while board(r+1,c) == 0
                            %while the piece below it is empty,
                            %Move the piece to the space below it
                            board(r+1,c) = board(r,c);
                            board(r,c) = 0;
                            r = r+1;
                        end
                        r = p;
                    end
                end
            end
        end

    elseif k == 'a'
        %left
        for r = 2:5
            for c = 3:5
                if board(r,c) ~= 0
                    if board(r,c) == board(r,c-1)
                        board(r,c-1) = board(r,c).*2;
                        board(r,c) = 0;
                    elseif board(r,c-1) == 0
                        p = c;
                        while board(r,c-1) == 0
                            board(r,c-1) = board(r,c);
                            board(r,c) = 0;
                            c = c-1;
                        end
                        c = p;
                    end
                end
            end
        end

    elseif k == 'd'
        %right
        for r = 2:5
            for c = 4:-1:2
                if board(r,c) ~= 0
                    if board(r,c) == board(r,c+1)
                        board(r,c+1) = board(r,c).*2;
                        board(r,c) = 0;
                    elseif board(r,c+1) == 0
                        p = c;
                        while board(r,c+1) == 0
                            board(r,c+1) = board(r,c);
                            board(r,c) = 0;
                            c = c+1;
                        end
                        c = p;
                    end
                end
            end
        end

    elseif k == 'w'
        %up
        for r = 3:5
            for c = 2:5
                if board(r,c) ~= 0
                    if board(r,c) == board(r-1,c)
                        board(r-1,c) = board(r,c).*2;
                        board(r,c) = 0;
                    elseif board(r-1,c) == 0
                        p = r;
                        while board(r-1,c) == 0
                            board(r-1,c) = board(r,c);
                            board(r,c) = 0;
                            r = r-1;
                        end
                        r = p;
                    end
                end
            end
        end
    end

    %removes the padding of NaNs
    board(1,:) = [];
    board(5,:) = [];
    board(:,1) = [];
    board(:,5) = [];


    %If the board is not unchanged after the move
    %, a 2 or a 4 is added to a random empty
    %spot on the board.
    if ~isequal(board,first)
        [x,y] = find(board==0);
        b = 2.*randi(2);
        c = randi(length(x));
        board(x(c),y(c)) = b;
    end

end

function res = poss(board)
%Checks if the board is still playable even if the
%board is full

    res = 0;

%Makes a single-layer padding of NaN-variables
%around the board.
    z = NaN(6,6);
    z(2:5,2:5) = board;


%If any of the board pieces has an equal and
%adjacent board piece, this function returns 1.
    for r = 2:5
        for c = 2:5
            if z(r,c) ~= 0
                if any([z(r-1,c),z(r+1,c),z(r,c+1),z(r,c-1)]==z(r,c));
                    res = 1;
                    return
                end
            end
        end
    end
end

function printboard(board)
%Prints the board. Not much to be said.

    for i =1:4
        fprintf('\n+----+----+----+----+')
        fprintf('\n|%4d|%4d|%4d|%4d|',board(i,:))
    end

    fprintf('\n+----+----+----+----+\n')

end

function res = printmenu()
%Prints the in-game menu.

    fprintf('\n"w/a/s/d" to move')
    fprintf('\n"l" to save to file')
    fprintf('\n"p" to quit to main menu')

    res = input('\n\nMake your choice and press Enter: ','s');


    %The output is the last character in
    %the input string. I found that while
    %playing fast, I typed in
    %two or more characters at once, so this
    %tries to fix that.

    if ~isempty(res)
        res = res(end);
    end

end

function b = dbread()
%Reads and returns the contents of a
%user-determined file.

    clc

    s = input('\nEnter file name to read from: ', 's');

    fid = fopen(s,'r');

    if fid == -1
        error('\nFile could not be accessed.')
    else
        for i = 1:4
            b(i,:) = str2num(fgetl(fid));
        end
    end

    fclose(fid);

end

function dbwrite(board)
%Writes the board to a user-determined file

    clc

    s = input('\nEnter file name to save in: ', 's');
    fid = fopen(s, 'w');

    if fid == -1
        error('\nFile could not be accessed.')
    else

        for i = 1:4
            fprintf(fid,'%d %d %d %d\n', board(i,:));
        end
    end

    fclose(fid);

end