I have a program that reads from several text files in a folder. What I don't understand is why it reads data from one file, but not another, when they are exactly the same except for the data. Can anyone give me any clue as to what might cause this?
Not without seeing the code you're using to read the files.
My best guess: you're reusing the ifstream and you're not calling clear() when re-opening. Thus, the eofbit stays set and all read operations on the later files fail.
All the buzzt!
CornedBee
"There is not now, nor has there ever been, nor will there ever be, any programming language in which it is the least bit difficult to write bad code."
- Flon's Law
Here is the code that opens a file. I have several text files, some of them work and others don't. Is there some kind of limit on the number of files a program can open?
Code:fstream f; char* temp; int array[20][20]; f.clear(); f.open("C:\\BC5\\BIN\\COEF\\SCREENS\\FIRSTENEMY.TXT", ios::in); if(!f) { moveto(200, 300); outtext("Cannot open file."); getch(); return ' '; } for (int j = 0; j < 20; j++) { for (int i = 0; i < 20; i++) { f.getline(temp, 4, ' '); scan(temp, array, i, j); } } f.close();
Yes, but you seem to be closing the file just fine. The limit only applies to how many files can be open at the same time.
All the buzzt!
"There is not now, nor has there ever been, nor will there ever be, any programming language in which it is the least bit difficult to write bad code."
- Flon's Law
You don't appear to be allocating any memory for temp.
Is there anything special I have to do to allocate memory other than declaring it as a normal variable?Originally Posted by Daved
It's not a "normal" (i.e. local) variable, it's a pointer, so you need to allocate a chunk of memory for it to point to. Ex.
Code:char* temp = new char[80]; ... delete [] temp; temp = NULL;
This indentation looks better and is more consistent; something to keep in mind writing readable code.Code:fstream f; char* temp; int array[20][20]; f.clear(); f.open("C:\\BC5\\BIN\\COEF\\SCREENS\\FIRSTENEMY.TXT", ios::in); if(!f) { moveto(200, 300); outtext("Cannot open file."); getch(); return ' '; } for (int j = 0; j < 20; j++) { for (int i = 0; i < 20; i++) { f.getline(temp, 4, ' '); scan(temp, array, i, j); } } f.close();
>> Is there anything special I have to do to allocate memory other than declaring it as a normal variable?
There's no need for dynamic memory allocation here, so I would allocate it as an array of the size you need. Your call to getline sets a maximum of 4 characters that can be read in. I don't remember whether that includes the terminating null or not (you should know find out... it's important). But to be safe, I'll allocate 5 characters in my example:Code:char temp[5];
> f.open("C:\\BC5\\BIN\\COEF
You should also consider having a separate projects directory for all your own work.
If you've set your compiler up properly, it shouldn't matter where everything is.
As it stands, you're one upgrade / patch / mistake away from losing stuff.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
I've tried your suggestions here, but it still will not open FIRSTENEMY.TXT, although it will open other files.
Now is BC5 something like the 32-bit version, or is it an older version which only understands 8.3 filenames (which your's isn't).
What about the short equivalent name of perhaps "FIRSTE~1.TXT"
Though do "dir /x" to find out the actual short name.
If this is the case, perhaps you might consider this to be yet another reason to leave the past behind.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
