File opening procedures

I know this might sound stupid but I would like to know what functions I need to use for working with files.
I need functions that will work with c++, since I use fopen in c but I get errors when I switch to cpp. I also need functions that will work under any compiler.

Thanks for any help
-Nar

Hi,

Since C is a subset of C++, I'm not sure why your file I/O isn't working. Maybe you should post some simple code demonstrating the problem.(You can check here for an example of C File I/O: http://www.owlnet.rice.edu/~comp320...notes/tut02-io/)

In C++ you can use streams for file I/O, but it's not quite as straight forward as giving you some function names. You have to create a pointer and assign it your file name, create an input file stream object with the pointer as the argument, and then use the object to read in the data.

const* char filename = "C:\\Data\\data1.txt";
ifstream inFile(filename);

//check to see if opening the file was successful:
if(!inFile)
{
cout<<"Failed to open file: "<<filename<<endl;
return 1;
}

int number = 0;

//read in the data until end of file is encountered:
while(!inFile.eof())
{
inFile>>number;

//do something here with the data you read in before reading in more data.
}

Thanks,

I used something like
f = fopen(path to file,"r+t");
fscanf(f,"%d",number);

the stuff compiled ok, but after the app ran it gave an exception.
I use borlan c++ builder 5.0, and when i do the same code in a
c application it works fine.

-Nar

Test the value of f returned by fopen(). If an error occured opening the file, the its value will be NULL. Using a NULL pointer is a leading cause of run-time errors.

Cleared it uot a bit

I tested for NULL, I found out it was NULL indeed when i tried

fopen("c:\autoexec.bat","r");

however it gave way when i tried to access a file in the
c:/tc/bin
direvtory.

I tried

chdir("c:");
fopen("autoexec.bat","r");

it didn't work again...

Any ideas

Double backslashes are your answer, my friend.
fopen("c:\\autoexec.bat","r");

Also, try this:
chdir("c:\\");
fopen("autoexec.bat","r");

and see if it works.

Hi,

I think your problem is with your filename

fopen("c:\autoexec.bat","r");

A forward slash is an escape character, so you need to use "\\" when you want to denote a "\". My compiler(VC6) will give me a warning for the single "\", but it will compile, and when I run it, I get null for the pointer. This should work:

fopen("c:\\autoexec.bat","r");

Thanks everyone!
-Nar