Question

Write a C++ program, tictac.cpp, that repeatedly reads in tic-tac-toe boards and for each one indicates if there is a winner and who won.

The board will be read in as 3x3 array of characters (x, o or . for a blank spot).

You are required to write the following functions to help solve the problem:

// input prompts the user for a board and inputs it

// into the given array

void input (char board [3][3]);

// print prints the board in nice format

void print (char board [3][3]);

How it should look:

Enter your board as characters (x, o or .):

o.x

..o

.x.

The board is:

o |   | x

-----------

   |   | o

-----------

   | x |

No winner!

Would you like to do another (y or n)? y

Enter your board as characters (x, o or .):

oxo

ox.

.xo

The board is:

o | x | o

-----------

o | x |

-----------

   | x | o

X wins!

Would you like to do another (y or n)? y

Enter your board as characters (x, o or .):

xoo

xox

ox.

The board is:

x | o | o

-----------

x | o | x

-----------

o | x |

O wins!

Would you like to do another (y or n)? n

Thanks for playing!

// win returns true if the given player has won on the

// given board, else it returns false

bool win (char board [3][3], char player);

You are required to use nested loops to write the functions input and print.

The back of this page shows a sample run of the program (input in bold). Your output should look at least as nice as that shown. You may assume that the board will be legal and there will be at most one winner.

Answer 1

C++ Program:

#include <iostream>

using namespace std;

// input prompts the user for a board and inputs it
// into the given array
void input (char board [3][3])
{
    int i, j;
    char ch;

    //Prompting user
    cout << "\n Enter your board as characters (x, o or .): \n";

    //Outer loop for rows
    for(i=0; i<3; i++)
    {
        //Inner loop for columns
        for(j=0; j<3; j++)
        {
            //Reading character
            cin >> ch;

            //Adding character to board
            if(ch == '.')
            {
                board[i][j] = ' ';
            }
            else
            {
                board[i][j] = ch;
            }
        }
    }
}

// print prints the board in nice format
void print (char board [3][3])
{
    int i, j;

    cout << "\n\n The board is: \n";

    cout << "\n |---|---|---| \n";

    //Outer loop for rows
    for(i=0; i<3; i++)
    {
        //Inner loop for columns
        for(j=0; j<3; j++)
        {
            //Printing character
            cout << " | " << board[i][j];
        }

        cout << " |";

        //Printing footer
        cout << "\n |---|---|---| \n";
    }
}

// win returns true if the given player has won on the
// given board, else it returns false
bool win (char board [3][3], char player)
{
    return (board[0][0] == player && board[0][1] == player && board[0][2] == player) ||
           (board[1][0] == player && board[1][1] == player && board[1][2] == player) ||
           (board[2][0] == player && board[2][1] == player && board[2][2] == player) ||
           (board[0][0] == player && board[1][0] == player && board[2][0] == player) ||
           (board[0][1] == player && board[1][1] == player && board[2][1] == player) ||
           (board[0][2] == player && board[1][2] == player && board[2][2] == player) ||
           (board[0][0] == player && board[1][1] == player && board[2][2] == player) ||
           (board[0][2] == player && board[1][1] == player && board[2][0] == player);

}

//Main function
int main()
{
    char userChoice;

    //Board
    char board[3][3];

    //Loop till user wants to quit
    do
    {
        //Reading board
        input(board);

        //Printing board
        print(board);

        //Deciding winner
        if(win(board, 'x'))
        {
            cout << "\n X wins! \n";
        }
        else if(win(board, 'o'))
        {
            cout << "\n o wins! \n";
        }
        else
        {
            cout << "\n No Winner! \n";
        }

        //Prompting user
        cout << "\n\n Would you like to do another (y or n)? ";
        cin >> userChoice;

    }while(userChoice == 'y' || userChoice == 'Y');

    cout << "\n Thanks for playing! \n";
    return 0;
}

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Sample Output: