Logical errors in Tic-Tac-Toe game - c

Question

I am trying to make a Tic-Tac-Toe game. I have written the code which I believe should work fine, but instead it is throwing logical errors.
#include <stdio.h>
#define size 9
char game_logic();
int game_win();
char array[size] = { '1', '2', '3', '4', '5', '6', '7', '8', '9' };
int main()
{
printf("\n\t\t Welcome to Tic-Tac-Toe game\n\n");
printf(" In this game, there will be two players taking turns for their moves\n\n");
printf("\t\t Player 1 = 'X' and Player 2 = 'O'\n\n");
for (int i = 0; i < size; i++)
{
printf("\t%c", array[i]);
if (array[i] == '1' || array[i] == '2' || array[i] == '4' ||
array[i] == '5' || array[i] == '7' || array[i] == '8')
{
printf(" |");
}
if (array[i] == '3' || array[i] == '6')
{
printf("\n -----------------------\n");
}
}
printf("\n\n");
do
{
game_logic();
} while (game_win() != 1 || game_win() != 2 || game_win != 3);
if (game_win() == 1)
{
printf("\nThe Player 1 has won the game\n");
}
else if (game_win() == 2)
{
printf("\nThe Player 2 has won the game\n");
}
else if (game_win() == 3)
{
printf("\nThe game is draw\n");
}
return 0;
}
char game_logic()
{
int n, m;
for (int i = 0; i < size; i++)
{
if (i % 2 == 0)
{
printf("Player 1, Please select the number = ");
scanf("%d", &n);
if (n > 0 && n < 10)
{
array[n] = 'X';
return array[n];
break;
}
}
else if (i % 2 != 0)
{
printf("Player 2, Please select the number = ");
scanf("%d", &m);
if (n > 0 && n < 10)
{
array[n] = 'O';
return array[n];
break;
}
}
}
}
int game_win()
{
game_logic();
if (array[0] == array[1] == array[2] == 'X' ||
array[2] == array[5] == array[8] == 'X' ||
array[6] == array[7] == array[8] == 'X' ||
array[0] == array[3] == array[6] == 'X' ||
array[0] == array[4] == array[8] == 'X' ||
array[2] == array[4] == array[6] == 'X' ||
array[1] == array[4] == array[7] == 'X' ||
array[3] == array[4] == array[5] == 'X')
{
return 1;
}
else
if (array[0] == array[1] == array[2] == 'O' ||
array[2] == array[5] == array[8] == 'O' ||
array[6] == array[7] == array[8] == 'O' ||
array[0] == array[3] == array[6] == 'O' ||
array[0] == array[4] == array[8] == 'O' ||
array[2] == array[4] == array[6] == 'O' ||
array[1] == array[4] == array[7] == 'O' ||
array[3] == array[4] == array[5] == 'O')
{
return 2;
}
else
{
return 3;
}
}
The basic plan was to execute game_logic which will decide how the game will run, it will take input from the user in the form of integers between 1 and 9. The number selected by the user will be replaced by X in the global array if player 1 inputs it, and will be replaced by O if player 2 selects it.
The results of game_logic is to be sent to the game_win which will determine if the game has been won or not by returning the values to the main function.
But when I ran the code, a loop occurs which says "Player 1, Please select the number = ", and this keeps on going by taking infinite input.
I have tried debugging it, but it is unable to help me. So can please suggest solutions for the logic made, or if my logic is correct.
The output:
Welcome to Tic-Tac-Toe game
In this game, there will be two players taking turns for their moves
Player 1 = 'X' and Player 2 = 'O'
1 | 2 | 3
-----------------------
4 | 5 | 6
-----------------------
7 | 8 | 9
Player 1, Please select the number = 3
Player 1, Please select the number = 2
Player 1, Please select the number = 3
Player 1, Please select the number = 4
Player 1, Please select the number = 3
Player 1, Please select the number = 2
Player 1, Please select the number = 2
Player 1, Please select the number = 3
Player 1, Please select the number = 4
and this keeps on going.

Answer 1

There are at least these major problems:
the test in the do ... while loop is incorrect: the loop iterates while (game_win() != 1 || game_win() != 2 || game_win != 3)... the third test compare the function name with 3 not return value of the function call, and even if you fix this problem, the test is always true since game_win() cannot be both 1 and 2 and 3. You should instead write:
do {
game_logic();
} while (game_win() != 0);
the tests in game_win() are incorrect: array[0] == array[1] == array[2] == 'X' should be written:
(array[0] == 'X' && array[1] == 'X' && array[2] == 'X')
game_win() does not properly test for a draw and never returns 0 in other cases.
if you call game_logic() in the loop, game_win() should not also call game_logic(). It would make sense for game_logic() to return the game_win() result, which would simplify the loop as:
while (game_logic())
continue;
the slot modified in game_logic() is incorrect: the number n is between 1 and 9, but the array elements start at 0 so you should modify array[n - 1].
the slot for player 2 is read into m, whereas the code uses n afterwards.
it would be more user friendly to redisplay the board before each turn.
Here is a modified version:
#include <stdio.h>
#define SIZE 9
int game_win(void);
int game_logic(int i);
char array[SIZE] = { '1', '2', '3', '4', '5', '6', '7', '8', '9' };
void display_board(void) {
printf("\n ");
for (int i = 1; i <= SIZE; i++) {
printf(" %c", array[i - 1]);
if (i == 1 || i == 2 || i == 4 || i == 5 || i == 7 || i == 8) {
printf(" |");
}
if (i == 3 || i == 6) {
printf("\n -----------------------\n ");
}
}
printf("\n\n");
}
int game_win(void) {
if ((array[0] == 'X' && array[1] == 'X' && array[2] == 'X') ||
(array[3] == 'X' && array[4] == 'X' && array[5] == 'X') ||
(array[6] == 'X' && array[7] == 'X' && array[8] == 'X') ||
(array[0] == 'X' && array[3] == 'X' && array[6] == 'X') ||
(array[1] == 'X' && array[4] == 'X' && array[7] == 'X') ||
(array[2] == 'X' && array[5] == 'X' && array[8] == 'X') ||
(array[0] == 'X' && array[4] == 'X' && array[8] == 'X') ||
(array[2] == 'X' && array[4] == 'X' && array[6] == 'X')) {
return 1;
}
if ((array[0] == 'O' && array[1] == 'O' && array[2] == 'O') ||
(array[3] == 'O' && array[4] == 'O' && array[5] == 'O') ||
(array[6] == 'O' && array[7] == 'O' && array[8] == 'O') ||
(array[0] == 'O' && array[3] == 'O' && array[6] == 'O') ||
(array[1] == 'O' && array[4] == 'O' && array[7] == 'O') ||
(array[2] == 'O' && array[5] == 'O' && array[8] == 'O') ||
(array[0] == 'O' && array[4] == 'O' && array[8] == 'O') ||
(array[2] == 'O' && array[4] == 'O' && array[6] == 'O')) {
return 2;
}
for (int i = 1; i <= SIZE; i++) {
if (array[i - 1] == '0' + i)
return 0;
}
return 3;
}
int game_logic(int i) {
for (;;) {
char buf[32];
int player, n;
char mark;
if (i % 2 == 0) {
player = 1;
mark = 'X';
} else {
player = 2;
mark = 'O';
}
printf("Player %d, Please select the number = ", player);
if (!fgets(buf, sizeof buf, stdin)) {
/* end of file reached: abort */
return -1;
}
if (sscanf(buf, "%d", &n) != 1 || n < 1 || n > 9) {
printf("please enter a number between 1 and 9\n");
continue;
}
if (array[n - 1] != '0' + n) {
printf("slot %d is already played\n", n);
continue;
}
array[n - 1] = mark;
return game_win();
}
}
int main() {
printf("\n\t\t Welcome to Tic-Tac-Toe game\n\n");
printf(" In this game, there will be two players taking turns for their moves\n\n");
printf("\t\t Player 1 = 'X' and Player 2 = 'O'\n\n");
for (int i = 0; i < SIZE; i++) {
display_board();
if (game_logic(i) != 0)
break;
}
switch (game_win()) {
case 0:
printf("\nThe game was aborted\n");
break;
case 1:
display_board();
printf("\nThe Player 1 has won the game\n");
break;
case 2:
display_board();
printf("\nThe Player 2 has won the game\n");
break;
case 3:
display_board();
printf("\nThe game is draw\n");
break;
}
return 0;
}

Answer 2

In the loop inside the game_logic function, it returns after Player1 entered a valid number. And then game_logic is called in a loop, so i gets never increased and this causes the endless loop.