Novice and Veteran - Problem 2, Solution in c

/* 
	Complete TicTacToe
*/
#include <stdio.h>

#define DEBUG

int grid[3][3];

int checkwin(int row, int col, int row_step, int col_step, int x_or_o) {

   int i;
   int sum = 0;

   for (i = 0; i < 3; i++) {

      if (grid[row][col] == x_or_o)
         sum++;

      row += row_step;
      col += col_step;
   }

   // The same symbol 3 times in a row/column/diagonal is a win
   if (sum == 3)
      return 1;
   else
      return 0;
}

int main () {

   int gamecount, i, row, col;
   int xwins, owins;

   // The first integer indicates how many games we will examine
   scanf(" %d", &gamecount);

   // Read each game from the input and determine its outcome
   for (i = 0; i < gamecount; i++) {

      // Re-initialize the number of X and O wins for each game
      xwins = 0;
      owins = 0;

      // Read in the 3 by 3 grid
      // It doesn't matter if input is in row major or column major order
      for (row = 0; row < 3; row++) {
         for (col = 0; col < 3; col++) {
            scanf(" %d", &grid[row][col]);
         }
      }

#ifdef DEBUG
      printf("\n");
      for (row = 0; row < 3; row++) {
         for (col = 0; col < 3; col++) {
            printf("%c", grid[row][col] ? 'X' : 'O');
         }
         printf("\n");
      }
      printf (":%d:", i);
#endif

      // Check for X's or O's in any rows
      for (row = 0; row < 3; row++) {
         xwins += checkwin(row, 0, 0, +1, 1);
         owins += checkwin(row, 0, 0, +1, 0);
      }

      // Check for X's or O's in any columns
      for (col = 0; col < 3; col++) {
         xwins += checkwin(0, col, +1, 0, 1);
         owins += checkwin(0, col, +1, 0, 0);
      }

      // Check for X's along the diagonals
      xwins += checkwin(0, 0, +1, +1, 1);
      xwins += checkwin(0, 2, +1, -1, 1);

      // Check for O's along the diagonals
      owins += checkwin(0, 0, +1, +1, 0);
      owins += checkwin(0, 2, +1, -1, 0);

      // Determine who wins
      if ((xwins == 0 && owins == 0) || (xwins > 1) || (owins > 1))
         printf("No One Wins\n");
      else if (xwins == 1 && owins == 0)
         printf("X Wins\n");
      else if (xwins == 0 && owins == 1)
         printf("O Wins\n");
      else
         printf("Both Win\n");
   }
}