Programming Forums > Application Development > C++

Ade · May 3rd, 2006, 7:39 AM

Hey guys, I've given up on trying to use MySQL++ with my graphics package for my game and have taken to using .txt files to hold the game data.

My programme is working fine with a few lines of data. However, when I try to add more lines to the file (the file is just lines of 8 numbers ie. 00100110 or 01108121) my programme just doesn't run. I don't get any errors with my code but I get the classic "suchandsuch.exe has encountered a problem and needs to close. We are sorry for the incovenience. Please tell microsoft about this problem."

Just wondering if programmes can only handle a small ammount of data from a .txt file? Does it use a lot of system resources?

Ta Ade

nnxion · May 3rd, 2006, 7:46 AM

No, you can use big files too, I've used a program which made a file of 11 GigaBytes, of course you don't load the whole file into memory when working with files that size. The limit on FAT32 are 4 GB files I believe.

Why not use SQLite? It's a self-contained, zero-configuration SQL database engine. PHP 5 uses it also.

You'll have to show us some code before we can say why suchandsuch.exe crashes.

Ade · May 3rd, 2006, 7:55 AM

This is the section of code that deals with extracting information from the file. When I comment this section out the programme no longer crashes.

(Toggle Plain Text)

	string line;
	int map_x[102];
        int map_y[102];
	int map_terrain[102];
	int map_extra[102];
	string map_x_st;
	string map_y_st;
	string map_terrain_st;
	string map_extra_st;
	int map_array_counter = 0;

  ifstream myfile ("mapfile.txt");
  if (myfile.is_open())
  {
    while (! myfile.eof() )
    {
      getline (myfile,line);
			map_x_st = line.substr (0,2);
			map_y_st = line.substr (2,2);
			map_terrain_st = line.substr (4,1);
			map_extra_st = line.substr (5,1);
			map_x[map_array_counter] = atoi(map_x_st.c_str());
			map_y[map_array_counter] = atoi(map_y_st.c_str());
			map_terrain[map_array_counter] = atoi(map_terrain_st.c_str());
			map_extra[map_array_counter] = atoi(map_extra_st.c_str());

		map_array_counter++;
    }
    myfile.close();
  }

This is a small section of the .txt file (mapfile.txt)

(Toggle Plain Text)

I used to this I was a good programmer, then I stopped using PHP! C++ is a lot of fun, but mainly it just wants to make me pull my hair out!!

Ta Ade.

OpenLoop · May 3rd, 2006, 8:04 AM

Why dont you modify your program to store the information in a dilimited way.

(Toggle Plain Text)

010410,010510,010610,010710,010810,010910,...

That will save you a lot of space on the disk.

nnxion · May 3rd, 2006, 8:43 AM

Quote:

Originally Posted by OpenLoop

Why dont you modify your program to store the information in a dilimited way.

(Toggle Plain Text)

010410,010510,010610,010710,010810,010910,...

That will save you a lot of space on the disk.

He is using a newline as delimter instead of a comma.

@Ade: Works fine for me..

(Toggle Plain Text)

#include <iostream>
#include <string>
#include <fstream>

using namespace std;

// TM DaWei
int uhOh(char * troubleInRiverCity)
{
	cerr << troubleInRiverCity << endl;
	return 1;
}

int main()
{
	string line;
	int map_x[102];
	int map_y[102];
	int map_terrain[102];
	int map_extra[102];
	string map_x_st;
	string map_y_st;
	string map_terrain_st;
	string map_extra_st;
	int map_array_counter = 0;

	ifstream myfile ("mapfile.txt");
	if (myfile.is_open())
	{
		while (! myfile.eof() )
		{
			getline (myfile, line);
			map_x_st = line.substr (0,2);
			map_y_st = line.substr (2,2);
			map_terrain_st = line.substr (4,1);
			map_extra_st = line.substr (5,1);
			map_x[map_array_counter] = atoi(map_x_st.c_str());
			map_y[map_array_counter] = atoi(map_y_st.c_str());
			map_terrain[map_array_counter] = atoi(map_terrain_st.c_str());
			map_extra[map_array_counter] = atoi(map_extra_st.c_str());

			// CONSOLE OUTPUT PLEASE :)
			cout << "map_x_st: " << map_x_st << endl;
			cout << "map_y_st: " << map_y_st << endl;
			cout << "map_terrain_st: " << map_terrain_st << endl;
			cout << "map_extra_st: " << map_extra_st << endl;

			cout << "map_x[" << map_array_counter << "]: " << map_x[map_array_counter] << endl;
			cout << "map_y[" << map_array_counter << "]: " << map_y[map_array_counter] << endl;
			cout << "map_terrain[" << map_array_counter << "]: " << map_terrain[map_array_counter] << endl;
			cout << "map_extra[" << map_array_counter << "]: " << map_extra[map_array_counter] << endl;

			cout << "map_array_counter: " << map_array_counter << endl << endl;


			map_array_counter++;
		}
		myfile.close();
	}
	else
		return uhOh("Error opening file");
	return 0;
}

Ade · May 3rd, 2006, 8:49 AM

It works fine for me too a that stage but I need the programme to handle like 1000ish lines. I've been able to make it take 100 six-digit numbers by putting them in a continuous line which is more than I was able to do having them on different lines. However, when I attempt more than about 100 it crashed again, I've tried using multiple files each with 50 entries in it but it doesn't like that either.

Could I use some sort of header file with the definitions in it? Would VS prefer that?

nnxion · May 3rd, 2006, 9:01 AM

That code above is not the problem. Maybe you can zip your stuff, and post it?

DaWei · May 3rd, 2006, 9:08 AM

This is plucked right out of my nether regions, but a good guess is you are trying to store more in an array than you allocated room for. Over and above that is the fact that

(Toggle Plain Text)

while (! myfile.eof() )

is a problematic way of winding up the read process successfully will all data intact and all data used. It's been covered thoroughly on this forum, as well as on other sites.

Cache · May 3rd, 2006, 9:27 AM

I'm starting to think I'm missing something here, lol. Does the following not sum up the problem?

(Toggle Plain Text)

int map_x[102];
int map_array_counter = 0;

// ...

while (! myfile.eof() )
{
   map_x[map_array_counter]
   
   // ...

   map_array_counter++;  // if ( map_array_counter > 101 ) { BOOM!; }
}

nnxion · May 3rd, 2006, 9:42 AM

Quote:

Originally Posted by Cache

I'm starting to think I'm missing something here, lol.

Hmm yeah, lol.

@David: Maybe I'm just forgetful, but I thought that only feof() was the problem because of:

Quote:

Originally Posted by C standard

7.19.10.2 The feof function

Synopsis

1 #include <stdio.h>
int feof(FILE *stream);

Description
2 The feof function tests the end-of-file indicator for the stream pointed to by stream.

Returns
3 The feof function returns nonzero if and only if the end-of-file indicator is set for stream.

It checks the end-of-file indicator, not the stream itself. In C++ the eof-bit is set instead of the 'end-of-file indicator', of course. I can't find more information on it, not on the forums nor on google.
As you have probably seen the feof problem is described in further detail here.

May 3rd, 2006, 7:39 AM	#1
Ade Hobbyist Programmer Join Date: Oct 2004 Location: England, UK Posts: 139 Rep Power: 0	How much can a C++ programme extract from a .txt file? Hey guys, I've given up on trying to use MySQL++ with my graphics package for my game and have taken to using .txt files to hold the game data. My programme is working fine with a few lines of data. However, when I try to add more lines to the file (the file is just lines of 8 numbers ie. 00100110 or 01108121) my programme just doesn't run. I don't get any errors with my code but I get the classic "suchandsuch.exe has encountered a problem and needs to close. We are sorry for the incovenience. Please tell microsoft about this problem." Just wondering if programmes can only handle a small ammount of data from a .txt file? Does it use a lot of system resources? Ta Ade __________________ Don't wound what you can't kill

May 3rd, 2006, 7:46 AM	#2
nnxion Programming Guru Join Date: Jun 2005 Location: elemental plane Posts: 1,429 Rep Power: 5	No, you can use big files too, I've used a program which made a file of 11 GigaBytes, of course you don't load the whole file into memory when working with files that size. The limit on FAT32 are 4 GB files I believe. Why not use SQLite? It's a self-contained, zero-configuration SQL database engine. PHP 5 uses it also. You'll have to show us some code before we can say why suchandsuch.exe crashes. __________________ "Employ your time in improving yourself by other men's writings, so that you shall gain easily what others have labored hard for." -- Socrates

May 3rd, 2006, 7:55 AM	#3
Ade Hobbyist Programmer Join Date: Oct 2004 Location: England, UK Posts: 139 Rep Power: 0	This is the section of code that deals with extracting information from the file. When I comment this section out the programme no longer crashes. (Toggle Plain Text) string line; int map_x[102]; int map_y[102]; int map_terrain[102]; int map_extra[102]; string map_x_st; string map_y_st; string map_terrain_st; string map_extra_st; int map_array_counter = 0; ifstream myfile ("mapfile.txt"); if (myfile.is_open()) { while (! myfile.eof() ) { getline (myfile,line); map_x_st = line.substr (0,2); map_y_st = line.substr (2,2); map_terrain_st = line.substr (4,1); map_extra_st = line.substr (5,1); map_x[map_array_counter] = atoi(map_x_st.c_str()); map_y[map_array_counter] = atoi(map_y_st.c_str()); map_terrain[map_array_counter] = atoi(map_terrain_st.c_str()); map_extra[map_array_counter] = atoi(map_extra_st.c_str()); map_array_counter++; } myfile.close(); } string line; int map_x[102]; int map_y[102]; int map_terrain[102]; int map_extra[102]; string map_x_st; string map_y_st; string map_terrain_st; string map_extra_st; int map_array_counter = 0; ifstream myfile ("mapfile.txt"); if (myfile.is_open()) { while (! myfile.eof() ) { getline (myfile,line); map_x_st = line.substr (0,2); map_y_st = line.substr (2,2); map_terrain_st = line.substr (4,1); map_extra_st = line.substr (5,1); map_x[map_array_counter] = atoi(map_x_st.c_str()); map_y[map_array_counter] = atoi(map_y_st.c_str()); map_terrain[map_array_counter] = atoi(map_terrain_st.c_str()); map_extra[map_array_counter] = atoi(map_extra_st.c_str()); map_array_counter++; } myfile.close(); } This is a small section of the .txt file (mapfile.txt) (Toggle Plain Text) 000010 000110 000210 000310 000410 000510 000610 000710 000810 000910 010010 010110 010210 010310 010410 010510 010610 010710 010810 010910 000010 000110 000210 000310 000410 000510 000610 000710 000810 000910 010010 010110 010210 010310 010410 010510 010610 010710 010810 010910 I used to this I was a good programmer, then I stopped using PHP! C++ is a lot of fun, but mainly it just wants to make me pull my hair out!! Ta Ade. __________________ Don't wound what you can't kill

May 3rd, 2006, 8:04 AM	#4
OpenLoop Expert Programmer Join Date: May 2005 Location: East Lansing, MI Posts: 663 Rep Power: 4	Why dont you modify your program to store the information in a dilimited way. (Toggle Plain Text) 010410,010510,010610,010710,010810,010910,... 010410,010510,010610,010710,010810,010910,... That will save you a lot of space on the disk.

May 3rd, 2006, 8:49 AM	#6
Ade Hobbyist Programmer Join Date: Oct 2004 Location: England, UK Posts: 139 Rep Power: 0	It works fine for me too a that stage but I need the programme to handle like 1000ish lines. I've been able to make it take 100 six-digit numbers by putting them in a continuous line which is more than I was able to do having them on different lines. However, when I attempt more than about 100 it crashed again, I've tried using multiple files each with 50 entries in it but it doesn't like that either. Could I use some sort of header file with the definitions in it? Would VS prefer that? __________________ Don't wound what you can't kill

May 3rd, 2006, 9:01 AM	#7
nnxion Programming Guru Join Date: Jun 2005 Location: elemental plane Posts: 1,429 Rep Power: 5	That code above is not the problem. Maybe you can zip your stuff, and post it? __________________ "Employ your time in improving yourself by other men's writings, so that you shall gain easily what others have labored hard for." -- Socrates

May 3rd, 2006, 9:08 AM	#8
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	This is plucked right out of my nether regions, but a good guess is you are trying to store more in an array than you allocated room for. Over and above that is the fact that (Toggle Plain Text) while (! myfile.eof() ) while (! myfile.eof() ) is a problematic way of winding up the read process successfully will all data intact and all data used. It's been covered thoroughly on this forum, as well as on other sites. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

May 3rd, 2006, 9:27 AM	#9
Cache Hobbyist Join Date: Sep 2005 Posts: 266 Rep Power: 4	I'm starting to think I'm missing something here, lol. Does the following not sum up the problem? (Toggle Plain Text) int map_x[102]; int map_array_counter = 0; // ... while (! myfile.eof() ) { map_x[map_array_counter] // ... map_array_counter++; // if ( map_array_counter > 101 ) { BOOM!; } } int map_x[102]; int map_array_counter = 0; // ... while (! myfile.eof() ) { map_x[map_array_counter] // ... map_array_counter++; // if ( map_array_counter > 101 ) { BOOM!; } }

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Programming Forums > Application Development > C++

How much can a C++ programme extract from a .txt file?