Using fopen on multiple files

Peter11111 · #1 27-Jul-2005, 19:53

I have about 100 csv files that I want to open. Each csv file containts similar data, and I need to analyse the first line of each csv file. The problem is how do I loop around fopen. Each csv file has incrememnting file numbers, so file1, file2, file3 ... The obvious solution is call fopen 100 separate times, but that is just being stupid.

L7Sqr · #2 27-Jul-2005, 20:27

I am assuming you want to know how to set up the file name for the files....
If that is the case, and the files are as you suggest...

CPP / C++ / C Code:

char * file_pat = "file%d";
char file[BUF];
int i = 1;
for (; i <= 100; +i) {
   snprintf (file, sizeof (file), file_pat, i);
   ...
   do what you want
   ...
}

Just replace file_pat to fit your actual pattern (or use your
pattern directly in the snprintf statement)

If you are talking about files that may or may not be in order (some numbers may be missing) and/or the number of files isnt know, you can use opendir and sscanf. If that is what you want post back and I'll give an example...

Peter11111 · #3 27-Jul-2005, 20:47

I think the best way to explain what I have done is by showing you:
This is what I have so far, and seems to work fine

CPP / C++ / C Code:

for(i=1;i<101;i++) 
{
 fp = fopen(argv[i], "r");  
 if ((fp) == NULL)
   fprintf(stderr, "Cannot open %s\n", argv[1]);
 else
   fgets(string , 100 , fp);
   ....

As you can see the problem is having 100 arguments on the command line.

L7Sqr · #4 28-Jul-2005, 05:10

So have the program take a format string as the argument.
for instance:

./program file_name_%03d.csv

Or some such that will match the pattern of your file.

Peter11111 · #5 29-Jul-2005, 21:42

Quote:

Originally Posted by L7Sqr

So have the program take a format string as the argument.
for instance:

./program file_name_%03d.csv

Or some such that will match the pattern of your file.

Have tried what you mentioned, but cannot seem to get it in the correct format
The file names are form1.cvs, form2.cvs ...

Dave Sinkula · #6 29-Jul-2005, 22:05

Quote:

Originally Posted by Peter11111

Have tried what you mentioned, but cannot seem to get it in the correct format

Expected input/output? Code sample (real, not "summarized")?

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