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Tic Tac Toe Program

suna6382 (8)
This is a tic tac toe program that has computer to act like a player 2 and it needs to have srand and rand with %. But, I can't seem to be able to do it. So please Help me!!! And it has to have ctime library!

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// Tic Tac Toe, by Sun A

// Include the libraries
#include <iostream>
#include <string>
#include <ctime>

//Use the standard namespace
using namespace std;

// Declare global variables
char Board[9];

// Declare functions
void showBoard ( );
bool moveIsValid (int m);
int whoWon ( ); //Returns 0 if no one has won, 1 if player 1 has won, and 2 if player 2 has won
int Move = rand() %7 + 1;

void main ( )
{
    // Seed the random number.
    srand(time(NULL));

   // Declare local variables
   string Player_1_Name;
   string Player_2_Name;
   int Whose_Turn = 1; // 1 means it's player 1's turn, 2 means it's player 2's turn
   int Move; // Stores where the player wants to move
   int Total_Moves = 0;

   //Assign values to the playing board
   Board[0] = '0';
   Board[1] = '1';
   Board[2] = '2';
   Board[3] = '3';
   Board[4] = '4';
   Board[5] = '5';
   Board[6] = '6';
   Board[7] = '7';
   Board[8] = '8';

   // Get player names
   cout << "Player 1: Please enter your name." << endl;
   cin >> Player_1_Name;
   cout << "Player 2: Computer." << endl;
   cin >> Player_2_Name;

   while (whoWon ( ) == 0 && Total_Moves < 9)
   {
      // Do this until the player chooses a valid move
      do
      {

         // Show the board
         showBoard ( );

         // Tell which player to move
         if (Whose_Turn == 1)
         {
            cout << Player_1_Name << ": It's your turn." << endl;
         }

         else
         {
            cout << Player_2_Name << ": It's your turn." << endl;
         }

         // Get the move
         cout << "Enter the number of the spot where you'd like to move." << endl;
         cin >> Move;
      } while (moveIsValid (Move) != true);

      // Add 1 to Total_Moves
      Total_Moves++;

      // Change whose turn it is
      switch (Whose_Turn)
      {
      case (1):
         {
            Board[Move] = 'x';
            Whose_Turn = 2;
            break;
         }

      case (2):
         {
            Board[Move] = 'o';
            Whose_Turn = 1;
         }
      }
   }

   // Show the board
   showBoard ( );

   if (whoWon ( ) == 1)
   {
      cout << Player_1_Name << " has won the game!" << endl;
   }

   else if (whoWon ( ) == 2)
   {
      cout << Player_2_Name << " has won the game!" << endl;
   }

   else
   {
      cout << "It's a tie game!" << endl;
   }

   system ("PAUSE");
}

void showBoard ( )
{
   cout << endl;
   cout << Board[0] << " | " << Board[1] << " | " << Board[2] << endl;
   cout << "--+---+--" << endl;
   cout << Board[3] << " | " << Board[4] << " | " << Board[5] << endl;
   cout << "--+---+--" << endl;
   cout << Board[6] << " | " << Board[7] << " | " << Board[8] << endl;
   cout << endl;
}

bool moveIsValid (int m)
{
   if (Board[m] != 'x' && Board[m] != 'o')
   {
      return true;
   }

   else
   {
      return false;
   }
}

int whoWon ( )
{
   if (Board[0] == Board[1] && Board[1] == Board[2])
   {
      if (Board[0] == 'x')
      {
         return 1;
      }

      else
      {
         return 2;
      }
   }

   if (Board[3] == Board[4] && Board[4] == Board[5])
   {
      if (Board[3] == 'x')
      {
         return 1;
      }

      else
      {
         return 2;
      }
   }

   if (Board[6] == Board[7] && Board[7] == Board[8])
   {
      if (Board[6] == 'x')
      {
         return 1;
      }

      else
      {
         return 2;
      }
   }

   if (Board[0] == Board[3] && Board[3] == Board[6])
   {
      if (Board[0] == 'x')
      {
         return 1;
      }
      else
      {
         return 2;
      }
   }

   if (Board[1] == Board[4] && Board[4] == Board[7])
   {
      if (Board[1] == 'x')
      {
         return 1;
      }
      else
      {
         return 2;
      }
   }
   if (Board[2] == Board[5] && Board[5] == Board[8])
   {
      if (Board[2] == 'x')
      {
         return 1;
      }
      else
      {
         return 2;
      }
   }

   if (Board[0] == Board[4] && Board[4] == Board[8])
   {
      if (Board[0] == 'x')
      {
         return 1;
      }
      else
      {
         return 2;
      }
   }

   if (Board[2] == Board[4] && Board[4] == Board[6])
   {
      if (Board[2] == 'x')
      {
         return 1;
      }
      else
      {

         return 2;
      }
   }
   return 0;
}
alextexasfan12 (57)
may want to change your void main to int main to start things off
Flaze07 (231)
also.....rather than using rand() (which makes the A.I stupid) makes tha A.I check for which moves can lead to victory :D
dhayden (5798)
You can have the computer choose by changing the loop from lines 52-72. You have to change the whole loop because most of what you have doesn't apply when the computer chooses:
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        do {
            if (Whose_Turn == 1) {
                // Show the board
                showBoard();

                cout << Player_1_Name << ": It's your turn." << endl;
                // Get the move
                cout << "Enter the number of the spot where you'd like to move.\
" << endl;
                cin >> Move;

            } else {
                // Computer selects random square
                Move = rand() % 9;
            }

        } while (moveIsValid(Move) != true);


Overall you have written a well organized, easy to read program. You show early talent as a programmer.

Below is a modified version of your program. Look for "dmh" in the comments to see what I changed.
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// Tic Tac Toe, by Sun A

// Include the libraries
#include <iostream>
#include <string>
#include <ctime>

//Use the standard namespace
using namespace std;

// Declare global variables
char Board[9];

// Declare functions
void showBoard();
bool moveIsValid(int m);
int whoWon(); //Returns 0 if no one has won, 1 if player 1 has won,
	      //and 2 if player 2 has won 

// dmh - This global variable is never used.
// int Move = rand() % 7 + 1;

int
main()
{
    // Seed the random number.
    srand(time(NULL));

    // Declare local variables
    string Player_1_Name;
    string Player_2_Name;
    int Whose_Turn = 1;		// 1 means it's player 1's turn, 2 means it's player 2's turn
    int Move;			// Stores where the player wants to move
    int Total_Moves = 0;

    //Assign values to the playing board
    Board[0] = '0';
    Board[1] = '1';
    Board[2] = '2';
    Board[3] = '3';
    Board[4] = '4';
    Board[5] = '5';
    Board[6] = '6';
    Board[7] = '7';
    Board[8] = '8';

    // Get player names
    cout << "Player 1: Please enter your name." << endl;
    cin >> Player_1_Name;

    // dmh - do you mean for the computer to have a name?
    cout << "Player 2: Computer." << endl;
    cin >> Player_2_Name;

    while (whoWon() == 0 && Total_Moves < 9) {
	// Do this until the player chooses a valid move
	do {
	    if (Whose_Turn == 1) {
		// Show the board
		showBoard();

		cout << Player_1_Name << ": It's your turn." << endl;
		// Get the move
		cout << "Enter the number of the spot where you'd like to move." << endl;
		cin >> Move;

	    } else {
		// Computer selects random square
		Move = rand() % 9;
	    }

	} while (moveIsValid(Move) != true);

	// Add 1 to Total_Moves
	Total_Moves++;

	// Change whose turn it is
	switch (Whose_Turn) {
	case (1):
	  // dmh - No need for braces in the cases, unless you define
	  // a local variable with a constructor.
	  Board[Move] = 'x';
	  Whose_Turn = 2;
	  break;
	case (2):
	  Board[Move] = 'o';
	  Whose_Turn = 1;
	}
    }

    // Show the board
    showBoard();

    // dmh - I changed this to a switch statement so (1) whoWon()
    // would be called only once and (2) because switch is more
    // appropriate since you're checking the value of a single
    // expression
    switch (whoWon()) {
    case 1:
	cout << Player_1_Name << " has won the game!" << endl;
	break;
    case 2:
	cout << Player_2_Name << " has won the game!" << endl;
	break;
    default:
	cout << "It's a tie game!" << endl;
	break;
    }

    system("PAUSE");
}

void
showBoard()
{
    cout << endl;
    cout << Board[0] << " | " << Board[1] << " | " << Board[2] << endl;
    cout << "--+---+--" << endl;
    cout << Board[3] << " | " << Board[4] << " | " << Board[5] << endl;
    cout << "--+---+--" << endl;
    cout << Board[6] << " | " << Board[7] << " | " << Board[8] << endl;
    cout << endl;
}

bool
moveIsValid(int m)
{
    // dmh - There's no need for an "if" statement here. Just return
    // the value of the boolean expression
    return (Board[m] != 'x' && Board[m] != 'o');
}

// dmh - here's a helper function that shows one way to reduce the
// duplicate code in whoWon().
int charToWinner(char ch)
{
    if (ch == 'x') {
	return 1;
    } else {
	return 2;
    }
}
    
int
whoWon()
{
    if (Board[0] == Board[1] && Board[1] == Board[2]) {
	// dmh - use helper function to reduce duplicate code
	return charToWinner(Board[0]);
    }

    if (Board[3] == Board[4] && Board[4] == Board[5]) {
	return charToWinner(Board[3]);
    }

    if (Board[6] == Board[7] && Board[7] == Board[8]) {
	return charToWinner(Board[6]);
    }

    if (Board[0] == Board[3] && Board[3] == Board[6]) {
	return charToWinner(Board[0]);
    }

    if (Board[1] == Board[4] && Board[4] == Board[7]) {
	return charToWinner(Board[1]);
    }
    if (Board[2] == Board[5] && Board[5] == Board[8]) {
	return charToWinner(Board[2]);
    }

    if (Board[0] == Board[4] && Board[4] == Board[8]) {
	return charToWinner(Board[0]);
    }

    if (Board[2] == Board[4] && Board[4] == Board[6]) {
	return charToWinner(Board[2]);
    }
    return 0;
}

jonnin (11437)
On the random moves / search for a good move ..

TTT is a classic example of very simple AI concepts. The first is pruning... eliminate moves that are illegal or lead to an immediate loss. The second is transposition tables, which is having the same board except mirrored (on x, y, or a diagonal!) or rotated. With the tables, there are only a very few possible actual games move by move, so you can easily outline every possible outcome and choose the best next move. Its a little advanced, but its an excellent exercise.

Another approach is opening move logic. If I recall, if the computer moves first, every move can be forced as the human must defend to a draw or lose. Human moves first is harder because you have the same scenario defense moves but you also have counter/win/take the lead moves if the human makes a mistake.

Many of these concepts are used in chess, a much more advanced game that continues to have improvements in the algorithms after many decades of study.
suna6382 (8)
@dheydan
THnak you so much for your help! I would never have beeen able to figure that out:(
and thanks for such a lovely compliment too!
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