Tic-tac-toe in C

#include <stdio.h>

int main()
{
    char gameTable[3][3] = {{'_','_','_'},{'_','_','_'},{'_','_','_'}};
    int i, j;
    char currentPlayer;
    int isWin;
    int turns;

    for (turns = 0; turns < 9; turns++) {
        currentPlayer = (turns % 2 == 0 ? 'O' : 'X');

        printf("Game state: \n");
        for (i=0; i<3; i++) {
            for (j=0; j<3; j++) {
                printf("%c ", gameTable[i][j]);
            }
            printf("\n");
        }
        printf("\n");

        do {
            printf("Enter player %c's placement, (\"row col\" counting from 0): ", currentPlayer);
            scanf(" %d %d", &i, &j);
        } while (i < 0 || i > 2 || j < 0 || j > 2 || gameTable[i][j] != '_');
        printf("\n");

        gameTable[i][j] = currentPlayer;

        //Checking winning. Could be optimised to check after 5 turns.
        //Check left-to-right
        for (i=0; i<3; i++) {
            if (gameTable[i][0] == '_') continue;
            isWin = 1;
            for (j=1; j<3; j++) {
                if (gameTable[i][j] != gameTable[i][0]) {
                    isWin = 0;
                    break;
                }
            }
            if (isWin == 1) break;
        }

        if (isWin == 1) break;

        //Check Top-to-bottom
          for (j=0; j<3; j++) {
            if (gameTable[0][j] == '_') continue;
            isWin = 1;
            for (i=1; i<3; i++) {
                if (gameTable[i][j] != gameTable[0][j]) {
                    isWin = 0;
                    break;
                }
            }
            if (isWin == 1) break;
        }

        if (isWin == 1) break;

        //Check corners
        for (i=0; i<3; i+=2 /* Skip middle column */) {
            if (gameTable[i][i] == '_') continue;
            isWin = 1;
            for (j=1; j<3; j++) {
                if (gameTable[j][j] != gameTable[i][i]) {
                    isWin = 0;
                    break;
                }
            }
            if (isWin == 1) break;
        }

        if (isWin == 1) break;
    }

    printf("Game state: \n");
    for (i=0; i<3; i++) {
        for (j=0; j<3; j++) {
            printf("%c ", gameTable[i][j]);
        }
        printf("\n");
    }
    printf("\n");

    if (isWin == 1) {
        printf("The winner is '%c'\n", currentPlayer);
    }
    else {
        printf("It's a draw. No winner.");
    }

    return 0;
}