Thread: Array of ifstream

Originally Posted by strokebow

Code:

ifstream multiple[MaxFileCount];

This is a bunch of one way streets

Code:

multiple[j].open(Names[j], ios::out|ios::out);

This is you driving the other way

Thanks

I saw that :-) but was having other issues too:

Code:

CString temp1;
j = 1;
do
{
	temp1 = Names[0]; 
	temp1 += "\\";
	temp1 += Names[j];
	multiple[j].open(temp1, ios::in);
	j++;
} while(j < (Fnames + 1));

Running in debug and watching temp1... It gets set as Names[0] and no further amendments are made. The '\' and Names[j] are not concatenated.

Why is that?

Cheers.

Originally Posted by Salem

> ifstream multiple[MaxFileCount];
How big is MaxFileCount?

Compared to most other resources you can have (say bytes of allocated memory), the number of concurrent open files is a very small number on most systems.
At the low level, you'll encounter an errno value of
ENFILE The system limit on the total number of open files has been reached.

You can look up how this might appear in fstream ( as a reason for .bad() )

You should certainly be checking each open in turn for success.

Hi,

Thanks for your insight Salem.
MaxFileCount is set at 100. Each file is at most 2KB.

I have now included a check after each open. I didn't realise there was a system limit on the total number of open files.

I am trying to combine the data from several text files in to 1 CSV file. My thinking was, I'll open them all, and copy the data from each, line by line, in to one CSV file. I know it isn't the best but hopefully it works ?

Any ideas why my CString isn't concatenating in the do while loop (Above)?

MFC class

Basic CString Operations

The CString class is a .net class not a C++ class. For C++ you should be using std::string. Also the calls to open will require the use of std::string.c_str() member.

Jim

Sorry, I still don't get whats going on...

Code:

std::vector< TCHAR > fileNamesBuffer(MaxFileBuffer);
CString Names[MaxFileCount];
...
Names[j] = Names[j] + fileNamesBuffer[i];
...
CString temp1 = "";
temp1 = Names[0]; 
temp1 = temp1 + "\\";

After, temp1 = Names[0], adding "\\" or "anything" to temp1 will not get added.

I don't understand why?

Putting understanding aside for now...

I changed my CString to string (C++ style).

Now when I add the strings or use append() the strings add but there is a 0 in between each add.

So in the debug watch I'd have:

[14] 116 't' char
[15] 0 char
[16] 92 '\' char

Whereby the 't' is the last letter of the first string. Then there is a 0 that separates from the "\\" backslash that is suppose to come after the 't'.

Don't get it? How can I get rid of the 0 pease?

Cheers

Please show the current code that is causing the problems.

Jim