saving a fucntion to a file

[Spiderpig085]

how do i get a function to write to a file for me?? im getting the error

error: invalid use of void expression

i want to save my tic tac game board to this file in order to save it.....

am i going the right way about it??

if(save_or_not == 'y'| save_or_not == 'Y')
                {
                    fstream file;
                    file.open("save1.txt",ios::in|ios::out);
                    file.write(DrawBoard());
                    file.close();
                 }

im gonna thank you guy in advance cos i had a prob before and my god you guys are generous to take time to help out...

thanks from the young beginner!!

[Lerner]

I'd change the single | to a double ||.

The ostream method write() takes two parameters and I find it difficult to see how the return type of DrawBoard(), whatever that is, can provide both parameters. If DrawBoard() uses cout you could write a second version using an ofstream (or an fstream in ios::out mode) or you could wrtie DrawBoard() generically to accept a reference to any valid output stream with the location of the output being determined by the stream passed to the function.

[Spiderpig085]

Thanks for your reply and i got the syntax error on "||" but the drawboard function is what i would like to write to the file. it draws out the board in the text file so i can retrieve it and use it again.

[Ancient Dragon]

You can't draw to a text file. I don't know what your game looks like, but if it contains a 2d array called a Board

char Board[5][5]; 

// write to a file
ofstream out("save1.bin", ios::binary);
out.write(Board, sizeof(Board));

// read from file
ifstream in("save1.bin", ios::binary);
out.read(Board, sizeof(Board));

[Spiderpig085]

You can't draw to a text file. I don't know what your game looks like, but if it contains a 2d array called a Board

char Board[5][5]; 

// write to a file
ofstream out("save1.bin", ios::binary);
out.write(Board, sizeof(Board));

// read from file
ifstream in("save1.bin", ios::binary);
out.read(Board, sizeof(Board));

Ok i've been at his for a few days now. il show my whole cpp... well without all the checks for win... can you help??

#include <iostream.h>
#include <stdlib.h>
#include <fstream.h>
#include "XO.hpp"

int player1_win=0;
int player1_lose=0;
int player2_lose=0;
int player2_win=0;
int total_games=0;
int draw=0;



void DrawBoard(void);

int Game::new_game()
{

    int m,n;
    char game_option='y';
    while(game_option=='Y'||game_option=='y')
    {
        for (m=0;m<3;m++)for (n=0;n<3;n++)*Board[m][n]= '\0';
        int i,j,sum=0;
        while ( sum < 10)
        {
            if (sum == 0) DrawBoard();
            cout<<"Player 1 is 'X': choose the row and column(to exit row=8 & col=9)"<<endl;
            cout<<"Row : ";
            cin>>i;
            cout<<"Column : ";
            cin>>j;
            if(i == 8 && j == 9)
            {
                char save_or_not;
                cout<<"Would you like to save the game?"<<endl;
                cin>>save_or_not;
                if(save_or_not == 'y'|| save_or_not == 'Y')
                {
                    void Save_Game(char *Board[3][3]);
                    break;
                }
                else
                {
                    break;
                }
            }
            else
            {
            for (;i>3 || i<1 || j>3 || j<1 ||('X'==*Board[i-1][j-1]||'O'==*Board[i-1][j-1]);)
            {
                cout<<"Sorry boy, but you gotta choose another place.\n";cout<<"row : ";cin>>i;cout<<"column : ";cin>>j;
            }
            *Board[i-1][j-1]='X';
            sum++;
            DrawBoard();

        //check if wins
            if (*Board[0][0]=='X' && *Board[0][0]==*Board[1][1] && *Board[1][1]==*Board[2][2])
            {
                player1_win++;
                player2_lose++;
                total_games++;
                cout<<"Player 1 wins"<<endl;
                break;
             }
            if (sum == 9)
            {
                cout<<"The game is over and no one wins, hahaha, your both low+!!"<<endl;
                total_games++;
                draw++;
                break;
            } //sum=9 because there are only 9 boxes in the game
            //player 2's turn

            cout<<"Player 2 is 'O': choose the row and column"<<endl;
            cout<<"Row : ";
            cin>>i;
            cout<<"Column : ";
            cin>>j;
            }



}
cout<<"\nWould you like to play again??? (Y - N)\n";
cin>>game_option;
}
      system("PAUSE");
      return 0;
}


void Game::Detail_Games(int player1_win,int player1_lose,int player2_lose,int player2_win)
{

    cout<<"-----------------------"<<endl;
    cout<<"|Player Results     | |"<<endl;
    cout<<"-----------------------"<<endl;
    cout<<"|Player 1 Wins:     |"<<player1_win<<"|"<<endl;
    cout<<"|Player 1 Lose(s):  |"<<player1_lose<<"|"<<endl;
    cout<<"|-------------------|-"<<"|"<<endl;
    cout<<"|Total Games:       |"<<total_games<<"|"<<endl;
    cout<<"|Total Draws:       |"<<draw<<"|"<<endl;
    cout<<"|-------------------|-"<<"|"<<endl;
    cout<<"|Player 2 Wins:     |"<<player2_win<<"|"<<endl;
    cout<<"|Player 2 Lose(s):  |"<<player2_lose<<"|"<<endl;
    cout<<"-----------------------"<<endl;
    cout<<""<<endl;
}

void Game::Load_Game()
{
}

void Game::DrawBoard(void)
{
//the play box
cout<<"\n\t      1   2   3\n"<<endl;
cout<<"\t   1  "<<*Board[0][0]<<" | "<<*Board[0][1]<<" | "<<*Board[0][2]<<endl;
cout<<"\t     ---|---|---\n";
cout<<"\t   2  "<<*Board[1][0]<<" | "<<*Board[1][1]<<" | "<<*Board[1][2]<<endl;
cout<<"\t     ---|---|---\n";
cout<<"\t   3  "<<*Board[2][0]<<" | "<<*Board[2][1]<<" | "<<*Board[2][2]<<"\n\n\n";
}

Game::Game()
{
	storageFile = new fstream("database.dat", fstream::in | fstream::out | fstream::binary);
}


void Game::Save_Game(char *Board[3][3])
{

ofstream out("save1.bin", ios::binary);

out.write(char *Board, sizeof(*Board[][]));

	cout<<"game saved";
}

To be honest im just making the program worse as i go along.. i am pretty much on the verge of quiting. any ideas how to save?

[Zjarek]

drawboard() is writing to standard input, and is returning void, so you can't print result to file. If you change function void Game::drawboard(void) to get reference to ostream, you will be able to print board on screen and to file.
PS: Why do you flush cout so much?

[Spiderpig085]

drawboard() is writing to standard input, and is returning void, so you can't print result to file. If you change function void Game::drawboard(void) to get reference to ostream, you will be able to print board on screen and to file.
PS: Why do you flush cout so much?

to be honest i just do it as good practice. When i get better at coding il try cut down but i wanna be better. any ideas on how to make that function reference ostream?

[Ancient Dragon]

to be honest i just do it as good practice.

Well, its not "good practice" to use endl to often because all it does is slow down your program. I recall a couple unix operating systems that needed flushing often so that you could see the output on the screen quicker, but that was nearly 30 years ago -- operating systems have improved a tad since then. Instead of endl you can simply use '\n' to move the cursor to the next line.