This document describes a Tic-Tac-Toe game program written in C++. The program allows two players to alternate placing X and O marks on a 3x3 grid to try and get three in a row. It uses functions to check for a winner after each turn and display the game board. The main parts of the program include global character variables, a main function controlling game flow with a do-while loop, a checkwin function that returns the winner or draw result, and a board function to print the current game state.

1. INTRODUCTION:
Tic-tac-toe (or Noughts and crosses, Xs and Os) is a pencil-and-paper
game for two players, X and O, who take turns marking the spaces in a
3×3 grid. The player who succeeds in placing three respective marks in a
horizontal, vertical, or diagonal row wins the game.
This program is a game program, Tic Tac Toe. Most of us have played this
game in school days, I make a C++ program on it.
PURPOSE: The purpose of this game is how we can use
functions and the if , else if statements in C++ .
HOW TO PLAY:
 In this game we see (3*3)=9 square shape box's.
 The identify symbol of player 1 is ( X ),and player 2 is( O ).
 When player 1 enter a number (1-9) ,the symbol ( x ) take position in
that number.

2.  similarly player 2 enter his/her number, and the symbol ( O )take
that position which number he/she input.
 When a symbol ( X ) or ( O )full fill a column, row, or diagonal first
this symbol player will be win.
4 Major Part Of Program.
1.Char type global variable.
2.Main function
3. Checkwin function.
4. Board function.
1. Char type global variable:
In this program we use only 1 header file #include<iostream.h>,
because this header file is the definition of the input or output object.
After this I make a character type global variable starting 0 to 9.
MAJOR PART OF PROGRAM
DETAILS OF CODE

3. 2.Main function: After this I declared 2 functions checkwin and
board.
After this the Main function is started Main logical and arithmetical steps
occurred in this function. I declared variables and assign player variable to
1.
I use do while loop in this program. First of all I call the board function to
display the main structure of game.
This function display the structure as :
After this first player enters a number (1 to 9) and the control according to
that number check the conditions that I made in the if else if structure . I
use a variable choice that save the number of user. And mark variable

4. assign player 1 X sign and 0 sign to second player. After the if else if
structure I mention if the user enter wrong number not from 1 to 9 then
computer display that the user enter invalid number. After this in each
case main function call the checkwin function that check any player wins
or not. If player is win then its display the result who is the winer with a
beep . and if there is not, then the game will be continue. The result of
checkwin function is save in the variable i and loop condition is running
until condition becomes false.

5. 3.Checkwin function: It is the function, used for detecting the
winner or determining the drawn result. In this function all conditions are
given. Any condition is true then this function return the result 1 and loop
will be terminated and if the game draw the function return the result 0.
Or the game will be continue this function return -1 and loop will not be
terminated.

6. 4.Board function: It is the function used for printing out playing
board.

7. COMPLETE SOURCE CODE

9. SCREEN SHOTS OF PROGRAM:

10. END
********************************************************