The simplest C++ Tic Tac Toe game ever

The simplest C++ Tic Tac Toe game ever

This is the simplest C++ Tic Tac Toe game ever, it`s made using only the most basic statements: cout, cin, variables, if/else/else if, switch/case and loops

The game uses 9 variables, one for each square of the Tic Tac Toe game board, each of them can have 3 different value:

0 - free square
1 - occupied by an x
2 - occupied by a 0

The board is redrawn after each move in a loop. The whole action of the game happens in this loop. First the board is checked for an eventual winner or for a tie. If the game is not over yet than it`s time to move. First the move is checked, if it`s not a valid move a message is displayed and the player needs to pick an another square, if the move is valid than the loop runs again, but this time is the other player`s turn.

#include <iostream>

using namespace std;

int main(){
//These variables are holding the value of each square (0 = free, 1 = x, 2 = o)
int one = 0;
int two = 0;
int three = 0;
int four = 0;
int five = 0;
int six = 0;
int seven = 0;
int eight = 0;
int nine = 0;
//This holds the number of the current player (1 = player1(x), 2 = player2(o)
int turn = 1;
//These variables are holding the row and column number inputted by a player
int row;
int column;
//These variables will be used later to check if a move is valid or not
bool validmove;
bool validrow;
bool validcolumn;
//The bellow variable holds the number of the winner, when the value is not 0 means the game is over
int winner = 0;
//The game loops again and again until somebody wins or it`s tie (winner = 3)
while(winner == 0){
//Draw the board from simple +,- and | characters
cout << "1 2 3" << endl << "+---+---+---+" << endl << "1 | ";
if(one == 0){
//For each square the variable of that square is checked, and based on it`s value a character is written (0 - nothing, 1 = x, 2 = o)
cout << "|";
}
else if(one == 1){
cout << "x |";
}
else{
cout << "o |";
}
if(two == 0){
cout << " |";
}
else if(two == 1){
cout << " x |";
}
else{
cout << " o |";
}
if(three == 0){
cout << " |";
}
else if(three == 1){
cout << " x |";
}
else{
cout << " o |";
}
cout << endl << "+---+---+---+" << endl << "2 | ";
if(four == 0){
cout << "|";
}
else if(four == 1){
cout << "x |";
}
else{
cout << "o |";
}
if(five == 0){
cout << " |";
}
else if(five == 1){
cout << " x |";
}
else{
cout << " o |";
}
if(six == 0){
cout << " |";
}
else if(six == 1){
cout << " x |";
}
else{
cout << " o |";
}
cout << endl << "+---+---+---+" << endl << "3 | ";
if(seven == 0){
cout << "|";
}
else if(seven == 1){
cout << "x |";
}
else{
cout << "o |";
}
if(eight == 0){
cout << " |";
}
else if(eight == 1){
cout << " x |";
}
else{
cout << " o |";
}
if(nine == 0){
cout << " |";
}
else if(nine == 1){
cout << " x |";
}
else{
cout << " o |";
}
cout << endl << "+---+---+---+" << endl << endl;
//The following several lines will check if the game is over or not
//Check`s the first line of the board for a winner combination (xxx or ooo)
if(one == two && two == three && one != 0){
//If the three squares have the same value and they are not free, then the winner is the player with the number from one of those squares
winner = one;
}
//Checks the second line
if(four == five && five == six && four != 0){
winner = four;
}
//Checks the third line
if(seven == eight && eight == nine && seven != 0){
winner = seven;
}
//Checks the first column
if(one == four && four == seven && one != 0){
winner = one;
}
//Checks the second column
if(two == five && five == eight && two != 0){
winner = two;
}
//Checks the third column
if(three == six && six == nine && three != 0){
winner = three;
}
//Checks the diagonal from top left to bottom right
if(one == five && five == nine && one != 0){
winner = one;
}
//Checks the diagonal from bottom left to top right
if(three == five && five == seven && three != 0){
winner = three;
}
//If nobody wins this turn it checks to see if the board is full or not
if(one != 0 && two != 0 && three != 0 && four != 0 && five != 0 && six != 0 && seven != 0 && eight != 0 && nine != 0 && winner == 0){
//If the table is full, then it`s tie
winner = 3;
}
//If somebody won or it`s a tie shows a message and break out from the loop - the game is over
if(winner == 1 || winner == 2){
cout << "Congratulations! Player " << winner << " is the winner!";
break;
}
else if(winner == 3){
cout << "Tie!";
break;
}
If the game is nor over yet than it writes a "Player x`s turn:" - where x is the number of the player (1 or 2)
cout << "Player " << turn << "'s turn:" << endl;
validmove = false;
//Loops until the player makes a valid move
while(!validmove){
validrow = false;
//Loops until the player chooses a valid row
while(!validrow){
cout << "Row: ";
cin >> row;
if(row == 1 || row == 2 || row == 3){
validrow = true;
}
else{
cout << endl << "Invalid row!" << endl;
}
}
validcolumn = false;
//Loops until the player chooses a valid column
while(!validcolumn){
cout << "Column: ";
cin >> column;
if(column == 1 || column == 2 || column == 3){
validcolumn = true;
}
else{
cout << endl << "Invalid column!" << endl;
}
}
//After the user selects a valid row and column number the changes are applied to the game board and the variable of the selected square if it`s not occupied and it changes the value of the validmove variable from false to true
switch(row){
case 1:
if(column == 1){
if(one == 0){
one = turn;
validmove = true;
}
}
else if(column == 2){
if(two == 0){
two = turn;
validmove = true;
}
}
else{
if(three == 0){
three = turn;
validmove = true;
}
}
break;
case 2:
if(column == 1){
if(four == 0){
four = turn;
validmove = true;
}
}
else if(column == 2){
if(five == 0){
five = turn;
validmove = true;
}
}
else{
if(six == 0){
six = turn;
validmove = true;
}
}
break;
case 3:
if(column == 1){
if(seven == 0){
seven = turn;
validmove = true;
}
}
else if(column == 2){
if(eight == 0){
eight = turn;
validmove = true;
}
}
else{
if(nine == 0){
nine = turn;
validmove = true;
}
}
}
//If validmove is still false, then the selected square is occupied and a message is displayed
if(!validmove){
cout << "The sellected square is occupied!" << endl << "Select again:" << endl;
}
else{
//Else if it was a valid move, then it`s the other player`s turn
if(turn == 1){
turn = 2;
}
else{
turn = 1;
}
}
cout << endl;
}
//The loop start`s over
}
system("pause");
}

The second version of this Tic Tac Toe game is ready with minor changes in the code, using a wee bit harder but more effective techniques: Tic Tac Toe v2