Thread: Assigning std::strings result in error

The following code can be found in one of my functions:

// ocv is the beginning of an std::list
// fin is an ifstream open to a file with data in it
// n, itemNumber, inRoom, and inArea are of type int
// str is a char *
// line and name are of type std::string

str = new char[150];

ocv->itemNumber = n;
fin >> n;
ocv->inRoom = n;
fin >> n;
ocv->inArea = n;

fin.getline(str, 100);
fin.getline(str, 100);
line = str;
if(line!="NONE") ocv->name = line;

// ------------------------------------------- //

I've stepped through this code in the Microsoft Visual C++ Debugger and discovered that in this part of the last line:
ocv->name = line;
the compiler experiences an unhandled exception (in the header file XSTRING, _PTR is NULL, which doesn't seem right). line and str both have the string that I expected it to have in it and the code still doesn't work. The problem is that I don't know what to do about this error. I would appreciate any help. Thanks!


-Joe

Code:

fin.getline(str, 100);
fin.getline(str, 100);

is this intentional? why would you read a second line into the buffer before using the first? i doubt this has anyting to do with your error though. can you provide the error the compiler gave you in addition to the debugger info?

Yes, ocv is an iterator to the correct location in an std::list. I'm sure it's reading into the list because I checked on itemNumber, inRoom, and inArea while debugging and they were the values in the text file.
I included fstream.h rather than fstream because occasionally I get errors when trying to close ifstreams and ofstreams when I use fstream. I have never figured this outand I know it better, so I decided to stay away from fstream and stick to fstream.h. I would be pleased if I could use all STL classes, so understanding why an ifstream or ofstream would give an error when closing would help me out.
As to why I used 2 getline calls, as zen knows (I believe), the '\n' is still in the buffer for the first call (because of the fin >> n; before it), so it is necessary. The following is the function's code. Beware: it may be a horrific from a programmer's perspective.

// obj_list is of type std::vector < std::list <Object> >
// ROOM_HASH is a constant (10)
//-------------- Code follows -----------------//
void fillObjectList()
{
std::ifstream fin("objects.odf");
std::string line;
std::list <Object>::iterator ocv, end_ocv;
int n;
char *str;
bool moreObjects = true;

str = new char[101];

fin >> n;
while(moreObjects)
{
ocv = obj_list[n % ROOM_HASH].begin();
end_ocv = obj_list[n % ROOM_HASH].end();

for(int x=0;x<=obj_list[n%ROOM_HASH].size();x++) ocv++;

ocv->itemNumber = n;
fin >> n;
ocv->inRoom = n;
fin >> n;
ocv->inArea = n;
fin.getline(str, 100);
fin.getline(str, 100);
line = str;
if(line!="NONE") ocv->name = line;

fin.getline(str, 100);
line = str;
if(line!="NONE") ocv->desc = line;

fin.getline(str, 100);
line = str;
if(line!="NONE") ocv->pluralDesc = line;

fin.getline(str, 100);
line = str;
if(line!="NONE") ocv->shortDesc = line;

fin.getline(str, 100);
line = str;
if(line!="NONE") ocv->actDesc = line;

// add to rooms
fin.getline(str, 100);
if(!(fin >> n)) moreObjects = false;
}
}