Problems with ofstream

This is a discussion on Problems with ofstream within the C++ Programming forums, part of the General Programming Boards category; Hi. I'm trying to use ofstream to save the data for the game I'm coding, but I've hit a snag. ...

  1. #1
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    Angry Problems with ofstream

    Hi. I'm trying to use ofstream to save the data for the game I'm coding, but I've hit a snag. When it saves the game, for some reason it outputs a null character to the start of the file, meaning that it can't load again properly. clear() and pause(1) are functions that I wrote to clear the screen and wait for any key, respectively, and they work fine. The saveto << line is just broken up so that it wraps right here, it's all one line in the code.

    Code:
    int save()
    {
       clear();
       cout<<"Saving game...\n";
       ofstream saveto ( "stockmarket.sav" );   //Open file to save to and input data, comma-delimited
       saveto.seekp ( 0 );
       saveto << playername <<","<< cash <<","<< boom <<","<< recession  <<","<< gi <<","<< gic <<","<< paid <<","<< week <<
          ","<< gamelength <<","<< stock[0] <<","<< stock[1] <<","<< stock[2] <<","<< stock[3] <<","<< stock[4] <<","<< stock[5] <<
          ","<< stock[6] <<","<< stock[7] <<","<< stock[8] <<","<< stock[9] <<","<< value[0] <<","<< value[1] <<","<< value[2] <<
          ","<< value[3] <<","<< value[4] <<","<< value[5] <<","<< value[6] <<","<< value[7] << ","<< value[8] <<","<< value[9];
       saveto.close();   //Close save file
       cout<<"Game saved successfully!\n";
       pause(1);
    }

  2. #2
    Sweet
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    Well if you are looking to clear a file each time you open it for a write you can use ios::trunc and just write to the file normally and it will start at the begining.
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  3. #3
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    Nope, didn't work.

  4. #4
    Sweet
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    Post the latest code.
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  5. #5
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    Same as the last time, but with
    Code:
    ofstream saveto ( "stockmarket.sav" );
    replaced with
    Code:
    ofstream saveto ( "stockmarket.sav" , ios::trunc );

  6. #6
    Sweet
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    Remove that seekp(0); and see what happens.
    Code:
    #include <iostream>
    #include <fstream>
    #include <string>
    
    struct player
    {
        std::string name;
        int money;
        int str;
        int def;
    };
    
    int main()
    {
        player mainP;
        std::ofstream toSave("player.sav",std::ios::trunc);
        
        mainP.name  = "Brian";
        mainP.money = 1000;
        mainP.str   = 10;
        mainP.def   = 10;
        
        toSave<<mainP.name<<std::endl
              <<mainP.money<<std::endl
              <<mainP.str<<std::endl
              <<mainP.def<<std::endl;
        toSave.close();
        return 0;
    }
    Output
    Code:
    Brian
    1000
    10
    10
    Last edited by prog-bman; 11-01-2005 at 07:39 PM.
    Woop?

  7. #7
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    Still has the same problem.

  8. #8
    Sweet
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    Well are you sure it is not how you are reading the file in. Because if you are doing what you said the output should be correct.
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  9. #9
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    Well, I was opening the output file in a good text editor, and it clearly printed the null character at the start of the file. But just in case, here is the loading half of the equation:

    Code:
    int load()
    {
       ifstream temp("stockmarket.sav");
       if(!temp.is_open())
       {
          cout<<"\nNo save file present.\n";
          pause(1);
          return -1;
       }   
       else
       {
          cout<<"\n";
          FILE * pFile;
          long lSize;
          char * buffer;
          char * output;
          int count = 0;
          pFile = fopen ( "stockmarket.sav" , "rb" );
          if (pFile==NULL) exit (1);
          fseek (pFile , 0 , SEEK_END);
          lSize = ftell (pFile);
          rewind (pFile);
          buffer = (char*) malloc (lSize);
          if (buffer == NULL) exit (2);
          fread (buffer,1,lSize,pFile);
          output = strtok(buffer,",");
          do
          {
             if ( output != NULL )
             {
                switch ( count )
                {
                   case 0:
                      playername = output;
                      break;
                   case 1:
                      cash = atoi( output );
                      break;
                   case 2:
                      boom = atoi( output );
                      break;
                   case 3:
                      recession = atoi( output );
                      break;
                   case 4:
                      gi = atoi( output );
                      break;
                   case 5:
                      gic = atoi( output );
                      break;
                   case 6:
                      paid = atof( output );
                      break;
                   case 7:
                      week = atoi( output );
                      break;
                   case 8:
                      gamelength = atoi( output );
                      break;
                   case 9:
                      stock[0] = atoi( output );
                      break;
                   case 10:
                      stock[1] = atoi( output );
                      break;
                   case 11:
                      stock[2] = atoi( output );
                      break;
                   case 12:
                      stock[3] = atoi( output );
                      break;
                   case 13:
                      stock[4] = atoi( output );
                      break;
                   case 14:
                      stock[5] = atoi( output );
                      break;
                   case 15:
                      stock[6] = atoi( output );
                      break;
                   case 16:
                      stock[7] = atoi( output );
                      break;
                   case 17:
                      stock[8] = atoi( output );
                      break;
                   case 18:
                      stock[9] = atoi( output );
                      break;
                   case 19:
                      value[0] = atoi( output );
                      break;
                   case 20:
                      value[1] = atoi( output );
                      break;
                   case 21:
                      value[2] = atoi( output );
                      break;
                   case 22:
                      value[3] = atoi( output );
                      break;
                   case 23:
                      value[4] = atoi( output );
                      break;
                   case 24:
                      value[5] = atoi( output );
                      break;
                   case 25:
                      value[6] = atoi( output );
                      break;
                   case 26:
                      value[7] = atoi( output );
                      break;
                   case 27:
                      value[8] = atoi( output );
                      break;
                   case 28:
                      value[9] = atoi( output );
                      break;
                }
             }
             output = strtok (NULL, ",");
             count++;
          }while ( output != NULL );
          fclose (pFile);   //Close file and clear buffer
          free (buffer);
       }
       screen();
    }

  10. #10
    Sweet
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    I am not the best person on reading in a certain type of input. But I can tell you that it I would not mix C and C++ file streams. As far as you code I think that this would work the same as above.
    Code:
    int load()
    {
        long lSize;
        char * buffer = NULL;
        char * output = NULL;
        int count = 0;
        
        ifstream temp("stockmarket.sav", ios::binary);
        
        if(!temp.is_open())
        {
            cout<<"\nNo save file present.\n";
            pause(1);
            return -1;
        }   
        else
        {
            cout<<"\n";
            
            temp.seekg(0,ios::end);
            
            lSize = temp.tellg();
            
            temp.seekg(0,ios::beg);
            
            buffer = new char[lSize];
            
            if (buffer == NULL)
            {
                exit (2);
            }
            
            temp.read(buffer,lSize);
            
            output = strtok(buffer,",");
            
            do
            {
                if ( output != NULL )
                {
                    switch ( count )
                    {                        
                       case 0:
                            playername = output;
                            break;
                       case 1:
                            cash = atoi( output );
                            break;
                       case 2:
                            boom = atoi( output );
                            break;
                       case 3:
                            recession = atoi( output );
                            break;
                       case 4:
                            gi = atoi( output );
                            break;
                       case 5:
                            gic = atoi( output );
                            break;
                       case 6:
                            paid = atof( output );
                            break;
                       case 7:
                            week = atoi( output );
                            break;
                       case 8:
                            gamelength = atoi( output );
                            break;
                       case 9:
                            stock[0] = atoi( output );
                            break;
                       case 10:
                            stock[1] = atoi( output );
                            break;
                       case 11:
                            stock[2] = atoi( output );
                            break;
                       case 12:
                            stock[3] = atoi( output );
                            break;
                       case 13:
                            stock[4] = atoi( output );
                            break;
                       case 14:
                            stock[5] = atoi( output );
                            break;
                       case 15:
                            stock[6] = atoi( output );
                            break;
                       case 16:
                            stock[7] = atoi( output );
                            break;
                       case 17:
                            stock[8] = atoi( output );
                            break;
                       case 18:
                            stock[9] = atoi( output );
                            break;
                       case 19:
                            value[0] = atoi( output );
                            break;
                       case 20:
                            value[1] = atoi( output );
                            break;
                       case 21:
                            value[2] = atoi( output );
                            break;
                       case 22:
                            value[3] = atoi( output );
                            break;
                       case 23:
                            value[4] = atoi( output );
                            break;
                       case 24:
                            value[5] = atoi( output );
                            break;
                       case 25:
                            value[6] = atoi( output );
                            break;
                       case 26:
                            value[7] = atoi( output );
                            break;
                       case 27:
                            value[8] = atoi( output );
                            break;
                       case 28:
                            value[9] = atoi( output );
                            break;
                    }
                }
                output = strtok (NULL, ",");
                count++;
            }while ( output != NULL );
        }
        screen();
    }
    I am not sure if this will work completely. I am sure someone else here knows more about C++ filestream tokenizing than me.
    Last edited by prog-bman; 11-01-2005 at 08:51 PM.
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  11. #11
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    What header files do I need for that? And what is the is. stuff for?

  12. #12
    Sweet
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    Whoops. I meant temp. You would include <fstream> and that should be it. If you wanted to get even more C++ you could use stringstream instead of atoi.
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  13. #13
    ^ Read Backwards^
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    Are you sure your playername variable does not have something on the front of it?

  14. #14
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    Apparently, it can't identify the c_str() function...

  15. #15
    Sweet
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    My bad agian. I was going to use a string but decided on a char * so just remove the c_str().
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