From f721c67b4533b10345760308e80b92e268a86fe5 Mon Sep 17 00:00:00 2001
From: r0nk <r0nk@simplecpu.com>
Date: Fri, 14 Aug 2020 22:16:27 -0500
Subject: [PATCH] full tic tac toe logic.

---
 src/main.cpp | 67 +++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 56 insertions(+), 11 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 6b777e3..ed223af 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -20,26 +20,71 @@ struct game_state {
 	char board[TILE_COUNT];
 };
 
-void game_turn(struct game_state * gs,int player_input){
-	if(player_input > TILE_COUNT && player_input < 0)
-		fprintf(stderr,"ERR: player input not in range.");
-	if(!gs->board[player_input])
-		gs->board[player_input]='O';
-	gs->turn++;
+int check_win_condition(struct game_state * gs, char player) {
+	int i;
+	for(i=0;i<3;i++){
+		//rows
+		if(gs->board[(i*3)]==player && gs->board[(i*3)+1]==player && gs->board[(i*3)+2]==player)
+			return 1;
+		//column
+		if(gs->board[i]==player && gs->board[i+3]==player && gs->board[i+6]==player)
+			return 1;
+	}
+	if(gs->board[0] == player && gs->board[4] == player && gs->board[8] == player)
+		return 1;
+	if(gs->board[2] == player && gs->board[4] == player && gs->board[6] == player)
+		return 1;
+
+	return 0;
 }
 
 void display_game_state(struct game_state * gs){
 	printf("turn %i:\n",gs->turn);
-	for(int i=0;i<TILE_COUNT;i++){
-		printf("[%i]:%c\n",i,gs->board[i]);
+	for(int i=0;i<3;i++){
+		for(int j=0;j<3;j++){
+			if(gs->board[(i*3)+j])
+				printf("%c",gs->board[(i*3)+j]);
+			else
+				printf("_");
+		}
+		printf("\n");
 	}
 }
 
+void player_turn(struct game_state * gs, char player, int input)
+{
+	if(input > TILE_COUNT && input < 0)
+		fprintf(stderr,"ERR: player input not in range.");
+	if(!gs->board[input])
+		gs->board[input]=player;
+	if(check_win_condition(gs,player)){
+		printf("player %c wins!\n",player);
+		gs->turn=-1;
+	}
+}
+
+void game_turn(struct game_state * gs,int player_input){
+	gs->turn++;
+	player_turn(gs,'O',player_input);
+	display_game_state(gs);
+	if(gs->turn==-1)
+		return;
+	player_turn(gs,'X',rand()%TILE_COUNT);
+	display_game_state(gs);
+}
+
+int exists_empty_tile(struct game_state * gs){
+	int i;
+	for(i=0;i<TILE_COUNT;i++)
+		if(!gs->board[i])
+			return 1;
+	return 0;
+}
+
 int main(){
 	srand(time(NULL));
-	struct game_state gs = {0};
-	while(gs.turn<TILE_COUNT){
+	struct game_state gs = {0,0};
+	while(exists_empty_tile(&gs) && gs.turn!=-1){
 		game_turn(&gs,get_player_input());
-		display_game_state(&gs);
 	}
 }