Replace a character with another character + Setting a tie game

This is for Homework

I have to create a game of TicTacToe for a project and I have two issues. Also I apologize if I'm violating a rule by having two questions within one post, If it's not allowed then I'd appreciate someone notifying me in the comments and I'll go ahead and break this into two separate posts. I'll post my code then ask my questions following the code.

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

char table[3][3];
void clear_table();
void player1_move();
void player2_move();
void the_matrix(); // Like the movie
char check_three();

int main() {
  srand(time(NULL));
  char win;

  printf("This program plays the game of Tic Tac Toe.\n");
  win = ' ';

  clear_table();

  do {

    the_matrix(); // Like the movie

    player1_move();

    win = check_three(); // Check win for player 1

    if (win != ' ')
      break;

    player2_move();

    win = check_three(); // Check win for player 2
  }

  while (win == ' ');
  the_matrix(); // Shows the final move+Like the movie
  if (win == 'O')

    printf("Congratulations, Player 1 wins!\n");

  else

    printf("Congratulations, Player 1 lost!\n");

  // the_matrix (); //Shows the final move+Like the movie

  return 0;
}

void clear_table() {
  // Creates empty spaces for the user and computer to enter stuff in

  int i, j, k;

  for (i = 0; i < 3; i++) {
    for (j = 0; j < 3; j++)
      // for(l = 0; k < 3; j++)
      table[i][j] = ' ';
  }
}

void player1_move() {
  // Moves that player 1 can and can't make

  int x, y, z;

  printf("Player 1 enter your selection[row, col]: ");
  scanf("%d, %d", &x, &y);
  x--;
  y--;
  // z--;

  if (table[x][y] != ' ') {
    printf("Space already taken, please try again.\n");

    player1_move();
  }

  else
    table[x][y] = 'O'; // O goes first for some reason
}

void player2_move() {
  // Needs work!!
  // Call srand in the main
  int a = rand() % 3;
  int b = rand() % 3;
  // Make it so the game would end in a tie when possible

  for (a = rand() % 3; a < 3; a++) {
    for (a = rand() % 3; b < 3;
         b++) // For loops causing issues in randomization?
      // for(c = 0; c < 3; c++)

      if (table[a][b] == ' ')
        break;
    if (table[a][b] == ' ') // Checks the rows and columns
      break;
  }
  if (a * b == 9)
    **Kinda works ? ** {
      printf("Game Over, No Player Wins\n");
      exit(0);
    }

  else

    table[a][b] = 'X';
}

void the_matrix() { // Like the movie
  **Get rid of the underscores **

   int m;

  printf("The current state of the board:\n");
  for (m = 0; m < 3; m++) {
    printf("%c_ %c_ %c_\n", table[m][0], table[m][1], table[m][2]);
  }
  printf("\n");
}

char check_three() {

  int w;
  // char table[3][3];

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

    if (table[w][0] == table[w][2] && table[w][0] == table[w][1])

      return table[w][0]; // Row Check
  }

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

    if (table[0][w] == table[2][w] && table[0][w] == table[1][w])

      return table[0][w]; // Col Check
  }

  if (table[0][0] == table[1][1] && table[1][1] == table[2][2])

    return table[0][0];

  if (table[0][2] == table[1][1] && table[1][1] == table[2][0])

    return table[0][2]; // Diag Check

  return ' ';
}

---

First Question

So my first question is with a draw game. On the player two function I have a snip of code set to determine a draw game. Initially I assumed that if the X's and O's were to multiply to 9 then that would mean that the board would be filled up then that would result in a draw game. [This is within my third function - player2_move near the end of the function] It kind of works, but sometimes the program just preemptively ends the game. It's a bit hard to test it because the computers moves are randomized and most of the times I've tried, I ended up winning accidentally. My question is what would I need to do to set up my program to essentially have a better way of determining a draw game.

---

Second Question

On my 4th function called the_matrix I need help with formatting. The assignment requires the format to be a little like this where if I were to enter in the coordinates 1,1 then the board would look like this:

O _ _ with the proceeding lines near the bottom to be blank. However as my program is right now, it looks like this:

O_ _ _

What I want to do is swap or replace the underscore with the user's input. Not entirely sure how to do that and any help would be appreciated.

I apologize if I violated any rules for stackoverflow by having two questions in one and I'm also sorry for this huge post.