What's the best/most efficent way to create a semi-intelligent AI for a tic tac toe game?
- by Link
basically I am attempting to make a a efficient/smallish C game of Tic-Tac-Toe. I have implemented everything other then the AI for the computer so far. my squares are basically structs in an array with an assigned value based on the square. For example
s[1].value = 1;
therefore it's a x, and then a value of 3 would be a o. My question is whats the best way to create a semi-decent game playing AI for my tic-tac-toe game? I don't really want to use minimax, since It's not what I need. So how do I avoid a a lot of if statments and make it more efficient.
Here is the rest of my code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
struct state{ // defined
int state; // 0 is tie, 1 is user loss, 2 is user win, 3 is ongoing game
int moves;
};
struct square{ // one square of the board
int value; // 1 is x, 3 is o
char sign; // no space used
};
struct square s[9]; //set up the struct
struct state gamestate = {0,0}; //nothing
void setUpGame(){ // setup the game
int i = 0;
for(i = 0; i < 9; i++){
s[i].value = 0;
s[i].sign = ' ';
}
gamestate.moves=0;
printf("\nHi user! You're \"x\"! I'm \"o\"! Good Luck :)\n");
}
void displayBoard(){// displays the game board
printf("\n %c | %c | %c\n", s[6].sign, s[7].sign, s[8].sign);
printf("-----------\n");
printf(" %c | %c | %c\n", s[3].sign, s[4].sign, s[5].sign);
printf("-----------\n");
printf(" %c | %c | %c\n\n", s[0].sign, s[1].sign, s[2].sign);
}
void getHumanMove(){ // get move from human
int i;
while(1){
printf(">>:");
char line[255]; // input the move to play
fgets(line, sizeof(line), stdin);
while(sscanf(line, "%d", &i) != 1) { //1 match of defined specifier on input line
printf("Sorry, that's not a valid move!\n");
fgets(line, sizeof(line), stdin);
}
if(s[i-1].value != 0){printf("Sorry, That moves already been taken!\n\n");continue;}
break;
}
s[i-1].value = 1;
s[i-1].sign = 'x';
gamestate.moves++;
}
int sum(int x, int y, int z){return(x*y*z);}
void getCompMove(){ // get the move from the computer
}
void checkWinner(){ // check the winner
int i;
for(i = 6; i < 9; i++){ // check cols
if((sum(s[i].value,s[i-3].value,s[i-6].value)) == 8){printf("The Winner is o!\n");gamestate.state=1;}
if((sum(s[i].value,s[i-3].value,s[i-6].value)) == 1){printf("The Winner is x!\n");gamestate.state=2;}
}
for(i = 0; i < 7; i+=3){ // check rows
if((sum(s[i].value,s[i+1].value,s[i+2].value)) == 8){printf("The Winner is o!\n");gamestate.state=1;}
if((sum(s[i].value,s[i+1].value,s[i+2].value)) == 1){printf("The Winner is x!\n");gamestate.state=2;}
}
if((sum(s[0].value,s[4].value,s[8].value)) == 8){printf("The Winner is o!\n");gamestate.state=1;}
if((sum(s[0].value,s[4].value,s[8].value)) == 1){printf("The Winner is x!\n");gamestate.state=2;}
if((sum(s[2].value,s[4].value,s[6].value)) == 8){printf("The Winner is o!\n");gamestate.state=1;}
if((sum(s[2].value,s[4].value,s[6].value)) == 1){printf("The Winner is x!\n");gamestate.state=2;}
}
void playGame(){ // start playing the game
gamestate.state = 3; //set-up the gamestate
srand(time(NULL));
int temp = (rand()%2) + 1;
if(temp == 2){ // if two comp goes first
temp = (rand()%2) + 1;
if(temp == 2){
s[4].value = 2; s[4].sign = 'o';
gamestate.moves++;
}else{
s[2].value = 2; s[2].sign = 'o';
gamestate.moves++;
}
}
displayBoard();
while(gamestate.state == 3){
if(gamestate.moves<10);
getHumanMove();
if(gamestate.moves<10);
getCompMove();
checkWinner();
if(gamestate.state == 3 && gamestate.moves==9){
printf("The game is a tie :p\n");
break;
}
displayBoard();
}
}
int main(int argc, const char *argv[]){
printf("Welcome to Tic Tac Toe\nby The Elite Noob\nEnter 1-9 To play a move, standard numpad\n1 is bottom-left, 9 is top-right\n");
while(1){ // while game is being played
printf("\nPress 1 to play a new game, or any other number to exit;\n>>:");
char line[255]; // input whether or not to play the game
fgets(line, sizeof(line), stdin);
int choice; // user's choice about playing or not
while(sscanf(line, "%d", &choice) != 1) { //1 match of defined specifier on input line
printf("Sorry, that's not a valid option!\n");
fgets(line, sizeof(line), stdin);
}
if(choice == 1){
setUpGame(); // set's up the game
playGame(); // Play a Game
}else {break;} // exit the application
}
printf("\nThank's For playing!\nHave a good Day!\n");
return 0;
}
