Tik-Tac-Toe
Tik Tac Toe is a Pascal built game.
How to write a Tic Tac Toe in Pascal?
Pascal is an imperative high-level procedural programming language. It was design by Niklaus Wirth released in 1970. It was developed following the pattern structure of ALGOL 60 language.
ALGOL was developed with a main goal, to describe algorithms. Pascal had more explicit goals, to be efficient with a compiler and when running a program. It also allowed developers to have a well-structured program.
Follow the images below and you will see how the program works. There are two players, User1 and User 2. When User1 gives a position number from 1 to 9, following a matrix form, an ‘X’ will be placed in that position. Then User2 gives its position and a ‘O’ will placed instead. If any of the users gives the same position as the other user, the program won’t let the user place any position and will prompt the user to give another number.
Flow Chart
Code
program TicTacToe;
{
size: the size of the board
}
const
size = 9;
{
tictac: is the type of array with a specific size
}
type
tictac = array [1..size] of integer;
{
endprocess: variable to determine if the game is over or not
user1: position that the user insert to put the character
user2: position that the machine insert to put the character
counter: variable used to read the board
turn: counter that indicate how many movements there are
boar: array where the movements are inserted
usermsg: variable to know what user is playing
message: variable to know who won or if its a draw
}
var
endprocess: boolean;
user1, user2, counter, turn: integer;
board: tictac;
usermsg, message: string;
{
This function prints characters
}
function printCharacter(j: integer): Char;
begin
if (board[j]=0) then
exit('O');
if (board[j]=1) then
exit('X');
if (board[j]=2) then
exit(' ');
end;
{
This function let us initialize the board with empty values represent by the number 2
}
function start_board(): real;
begin
for counter := 1 to size do
board[ counter ] := 2;
end;
{
This function let us validate if the user inserted a valid position
}
function valid_pos(pos: integer): boolean;
begin
if board[pos] = 2 Then
begin
valid_pos := true;
end
else
begin
valid_pos := false;
end;
end;
{
This function insert in the board in a specific position the value
}
function insert_board_user1(): real;
begin
board[user1] := 1;
turn := turn + 1;
end;
{
this function create a random number that is a position in the board,
then validate if that position is valid, if not create new position
}
function insert_board_machine(): real;
begin
user2 := random(9) + 1;
while not valid_pos(user2) do
begin
user2 := random(9) + 1;
end;
board[user2] := 0;
turn := turn + 1;
end;
{
print the board with the movements made by each user
}
function print_board(): real;
begin
writeln('==================', usermsg, '==================');
writeln(' [', printCharacter(1), ', ', printCharacter(2), ', ', printCharacter(3), ']');
writeln(' [', printCharacter(4), ', ', printCharacter(5), ', ', printCharacter(6), ']');
writeln(' [', printCharacter(7), ', ', printCharacter(8), ', ', printCharacter(9), ']');
writeln('=========================================');
end;
{
This function validate if the user1 win when make a movement
}
function valid_win_user1(): boolean;
begin
if (board[1] = 1) AND (board[2] = 1) AND (board[3] = 1) OR
(board[1] = 1) AND (board[4] = 1) AND (board[7] = 1) OR
(board[1] = 1) AND (board[5] = 1) AND (board[9] = 1) OR
(board[2] = 1) AND (board[5] = 1) AND (board[8] = 1) OR
(board[3] = 1) AND (board[5] = 1) AND (board[7] = 1) OR
(board[3] = 1) AND (board[6] = 1) AND (board[9] = 1) OR
(board[4] = 1) AND (board[5] = 1) AND (board[6] = 1) OR
(board[7] = 1) AND (board[8] = 1) AND (board[9] = 1) Then
begin
message := '¡User1 Win!';
endprocess := false;
valid_win_user1 := true;
end
else
begin
valid_win_user1 := false;
end;
end;
{
This function validate if the machine win when make a movement
}
function valid_win_user2(): boolean;
begin
if (board[1] = 0) AND (board[2] = 0) AND (board[3] = 0) OR
(board[1] = 0) AND (board[4] = 0) AND (board[7] = 0) OR
(board[1] = 0) AND (board[5] = 0) AND (board[9] = 0) OR
(board[2] = 0) AND (board[5] = 0) AND (board[8] = 0) OR
(board[3] = 0) AND (board[5] = 0) AND (board[7] = 0) OR
(board[3] = 0) AND (board[6] = 0) AND (board[9] = 0) OR
(board[4] = 0) AND (board[5] = 0) AND (board[6] = 0) OR
(board[7] = 0) AND (board[8] = 0) AND (board[9] = 0) Then
begin
message := '¡User2 Win!';
endprocess := false;
valid_win_user2 := true;
end
else
begin
valid_win_user2 := false;
end;
end;
{
All the logical
}
begin
{
print all the rules and how it works
}
writeln ('==================Guide==================');
writeln (' [1, 2, 3] ');
writeln (' [4, 5, 6] ');
writeln (' [7, 8, 9] ');
writeln ('-----------------------------------------');
writeln ('0: is the IA and represent the "O"');
writeln ('1: is the User1 and represent the "X"');
writeln ('-----------------------------------------');
writeln ('You need to insert numbers between 1-9');
writeln ('=========================================');
{
initialize the board, and the status program
}
start_board();
user1 := 0;
user2 := 0;
turn := 0;
endprocess := true;
{
main loop
}
while endprocess do
begin
{
user 1 insert a value
}
writeln('Insert position');
readln (user1);
{
validate if that position inserted is valid
}
if (user1 > 0) AND (user1 < 10) Then
begin
{
if the position is empty
}
if valid_pos(user1) Then
begin
{
insert into the board
print the movement
validate if that movement is the win or if is the last movement
}
insert_board_user1();
usermsg := 'USER1';
print_board();
if valid_win_user1() OR (turn = 9) Then
begin
if turn = 9 Then
begin
message := '¡Match draw!';
end;
break;
end;
{
insert into the board
print the movement
validate if that movement is the win or if is the last movement
}
usermsg := 'USER2';
insert_board_machine();
print_board();
if valid_win_user2() OR (turn = 9) Then
begin
if turn = 9 Then
begin
message := '¡Match draw!';
end;
break;
end;
end
else
begin
writeln('That position is occupied, insert other...');
continue;
end;
end
else
begin
writeln('Type a number between 1 and 9');
end;
end;
writeln(message);
end.