tictactoe.c

#include <stdio.h>

const char gamer[3] = "XO";

int same_size(char a[], char b[])
{
  int i;
  for(i = 0;; i++) {
    if(a[i] == '\0' || b[i] == '\0') {
      return a[i] == b[i];
    }
  }
}

void printer(char game[], char selector[])
{
  if(!same_size(game, selector)) {
    puts("TicTacToe printer input is not correct.");
    return;
  }

  printf("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n");
  puts("tic tac toe\n");

  char charrow[] = " %c | %c | %c   |   %c  %c  %c\n";
  char placer[] =  "---+---+---  |";

  int i;
  for(i = 0; i < 3; i++) {
    printf(charrow,
           game[3*i], game[3*i+1], game[3*i+2],
           selector[3*i], selector[3*i+1], selector[3*i+2]);
    if(i < 2)
      puts(placer);
  }
  puts("");
}

int select(char game[], char selector[], int runde)
{
  if(!same_size(game, selector)) {
    puts("select input is wrong.");
    return -1;
  }

  char selected[2];
  int selected_pos = -1;

  int dead_game = 1;
  int i;
  for(i = 0; game[i] != '\0'; i++) {
    if(game[i] == ' ') {
      dead_game = 0;
      break;
    }
  }

  while(!dead_game) {
    printf("\n%c ist am Zug\n\n", gamer[runde%2]);
    printf("Bitte wählen Sie eine Position: ");
    scanf("%1s", selected);

    int match = 0;

    for(i = 0; selector[i] != '\0'; i++) {
      if(selector[i] == selected[0]) {
        selected_pos = i;
        match = 1;
        break;
      }
    }

    if(!match)
      puts("\nDas Feld existiert nicht.");
    else if(game[selected_pos] != ' ') {
      puts("\nDas Feld ist belegt.");
      match = 0;
    }

    if(match) break;
  }

  return selected_pos;
}

char winner(char game[])
{
  if(!same_size(game, "123456789")) {
    puts("winner input has not the correct size");
    return '\0';
  }

  int winnerstrikes[8][3] = {
    {0, 1, 2},
    {3, 4, 5},
    {6, 7, 8},
    {0, 3, 6},
    {1, 4, 7},
    {2, 5, 8},
    {0, 4, 8},
    {2, 4, 6}
  };

  int i;
  for(i = 0; i < 8; i++) {
    if(game[winnerstrikes[i][0]] == game[winnerstrikes[i][1]] &&
       game[winnerstrikes[i][0]] == game[winnerstrikes[i][2]] &&
       game[winnerstrikes[i][0]] != ' ') {
      return game[winnerstrikes[i][0]];
    }
  }
  for(i = 0; i < 9; i++) {
    if(game[i] == ' ') {
      return ' ';
    }
  }
  return '\0';
}

int ki(char game[], int runde)
{
  char my = runde%2;
  int my_char = gamer[my];
  int i, j;

  int selecting[9] = {0, 0, 0, 0, 0, 0, 0, 0, 0};
  int gamefield[9] = {1, 1, 1, 1, 1, 1, 1, 1, 1};

  for(i = 0; i < 9; i++) {
    if(game[i] != ' ') {
      if(game[i] == my_char)
        gamefield[i] = 2;
      else
        gamefield[i] = 0;
    }
  }

  int combi[8][3] = {
    {0, 1, 2},
    {3, 4, 5},
    {6, 7, 8},
    {0, 3, 6},
    {1, 4, 7},
    {2, 5, 8},
    {0, 4, 8},
    {2, 4, 6}
  };

  for(i = 0; i < 8; i++) {
    for(j = 0; j < 3; j++) {
      int s = combi[i][j];
      if(gamefield[s] != 1) continue;
      int s1 = gamefield[combi[i][(j + 1) % 3]];
      int s2 = gamefield[combi[i][(j + 2) % 3]];

      // X X  32
      // O O  16
      // X -  8
      // - X  8
      // - O  4
      // O -  4
      // - -  2
      // O X  1
      // X O  1
      //
      // 2 == X == MY
      // 0 == O == Other
      // 1 == - == Empty

      if (s1 == 2 && s2 == 2) selecting[s] += 32;
      if (s1 == 0 && s2 == 0) selecting[s] += 16;
      if ((s1 == 2 && s2 == 1) || (s1 == 1 && s2 == 2)) selecting[s] += 8;
      if ((s1 == 0 && s2 == 1) || (s1 == 1 && s2 == 0)) selecting[s] += 4;
      if (s1 == 1 && s2 == 1) selecting[s] += 2;
      if ((s1 == 0 && s2 == 2) || (s1 == 2 && s2 == 0)) selecting[s] += 1;
    }
  }

  int choosed = -1;
  for(i = 0; i < 9; i++) {
    if(gamefield[i] == 1) {
      if(choosed == -1 || selecting[i] > selecting[choosed])
        choosed = i;
    }
  }

  return choosed;
}

int main()
{
  char game[10] = "         ";
  char selector[10] = "wersdfxcv";
  int runde = 0;

  while(winner(game) == ' ') {
    printer(game, selector);
    int selected;
    if(runde%2 == 0)
      selected = select(game, selector, runde);
    else
      selected = ki(game, runde);

    if(selected >= 0 && game[selected] == ' ') {
      game[selected] = gamer[runde++ % 2];
    }
  }

  printer(game, selector);

  switch(winner(game)) {
    case 'X':
    case 'O':
      printf("Spieler %c hat gewonnen.\n", winner(game));
      break;
    case '\0':
      puts("Es ist unentschieden.");
  }

  return 0;
}