tictactoe.c

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <math.h>
#include <time.h>

char board[3][3];
const char PLAYER = 'X';
const char COMPUTER = 'O';
void resetboard();
void printboard();
int checkspaces();
void playermove();
void computermove();
char checkwinner();
void printwinner(char);
int main(){
char winner = ' ';
char response;
do{
winner = ' ';
response = ' ';
resetboard();
while(winner == ' ' && checkspaces() != 0){
printboard();
playermove();
winner = checkwinner();
if (winner != ' ' || checkspaces() == 0){
break;
}
computermove();
winner = checkwinner();
if (winner != ' ' || checkspaces() == 0){
break;
}
}
printboard();
printwinner(winner);
printf("Would you like to play again? (Y/N)\n");
scanf(" %c", &response);
response = toupper(response);
}
while(response == 'Y');
printf("Thanks for playing!");
};
void resetboard(){
for(int i = 0; i < 3; ++i){
for(int j = 0; j < 3; ++j){
board[i][j] = ' ';
}
}
};
void printboard(){
printf(" %c | %c | %c ", board[0][0], board[0][1], board[0][2]);
printf("\n---|---|---\n");
printf(" %c | %c | %c ", board[1][0], board[1][1], board[1][2]);
printf("\n---|---|---\n");
printf(" %c | %c | %c ", board[2][0], board[2][1], board[2][2]);
printf("\n");
};
int checkspaces(){
int freespace = 9;
for(int i = 0; i < 3; ++i){
for(int j = 0; j < 3; ++j){
if(board[i][j] != ' '){
--freespace;
}
}
}
return freespace;
};
void playermove(){
int x;
int y;
do{
printf("Row Number? (1 - 3)\n");
scanf("%d", &x);
--x;
printf("Column Number? (1 - 3)\n");
scanf("%d", &y);
--y;
if(board[x][y] != ' '){
printf("Invalid move\n");
}
else{board[x][y] = PLAYER;
break;
}
}
while(board[x][y] != ' ');
};
void computermove(){
srand(time(0));
int x;
int y;
if (checkspaces() > 0){
do{
x = rand() % 3;
y = rand() % 3;
}
while(board[x][y] != ' ');
board[x][y] = COMPUTER;
}
else{
printwinner(' ');
}
};
char checkwinner(){
for(int i = 0; i < 3; ++i){
if(board[i][0] == board[i][1] && board[i][0] == board[i][2])
return board[i][0];
}
for(int i = 0; i < 3; ++i){
if(board[0][i] == board[1][i] && board[0][i] == board[2][i])
return board[0][i];
}
if(board[0][0] == board[1][1] && board[0][0] == board[2][2]){
return board[0][0];
}
if(board[0][2] == board[1][1] && board[0][2] == board[2][0]){
return board[0][2];
}
return ' ';
};
void printwinner(char winner){
if(winner == PLAYER){
printf("You win!\n");
}
else if(winner == COMPUTER){
printf("You lose!\n");
}
else{
printf("It's a draw!\n");
}
};