Thread: Manipulating Files

Im currently writting a small database program for school, and im having a lot of trouble manipulating data within the file. My program has to write to a file in the following manner

[Record #] Moviename,year,length,reference#

and that has been no problem

but now i need it to scan the file for a specific record number (all record numbers are written as [Record #00] etc), and i have no idea how to do it. Also, you have to be able to edit the information in the file, and i have no idea how to do that

can someone give me a website or some personal information on inter-file manipulation?

Ouch, I've been working on a VERY similar problem for the past couple weeks. My resolution was ultimately to use perl, but that's probably not going to work in your situation. I spent quite a bit of time reading through the regex.h header file, and the files associated with it. In my situation, the idea was a file with lines that looked like:

A:1:somefile:75:3

and I needed all of those in a seperate variable. The idea was to grab any number of chars up until the colon, and than between colons five times over. It seems to me that you want a similar approach, I just can't tell you how exactly to do it in C.

As far as writing to the file goes, fputs should work well. The syntax is:

fputs(pointer_to_string, FILE *stream);

I hope that I've been of some assistance. Please, do keep me posted as to how this progresses.

-starX
www.axisoftime.com

Code:

#include "stdio.h"
#include "stdlib.h"
#include "string.h"

#define EXIT_FAILURE	1;
#define EXIT_SUCCESS	0;

int main(int argc, char *argv[])
{
	FILE *fp; // File Handle
	char fpname[] = "Records.txt", r_string[] = "record #";
	const int MAX = 150;
	char line[MAX] = {0};

	if(argc < 2){
		printf(" Example: Ref.exe [record#]\n");
		return EXIT_FAILURE;
	}
	
	fp = fopen(fpname,"rb");
	if(!fp){
		printf(" Cannot find or open %s", fpname);
		return EXIT_FAILURE;
	}

	while(fgets(line, MAX, fp)!=NULL)
	{
		if(strstr(line,r_string) 
			        != NULL && strstr(line,argv[1]) != NULL)
			printf("%s",line);
	}

	return EXIT_SUCCESS;
}

Ok, create a file called "Records.txt", then place in stuff like the following.
[record #01] Moviename : BlahBlah Year : 2002 Length : 2hrs
[record #02] Moviename : Aname Year : 2001 Length : 1hr 30 min
.................., ................., ., .........., ........, ., ......., .........., ., ....etc

Then run the program like so,
Example : ref.exe 01
Output : [record #01] Moviename : BlahBlah Year : 2002 Length : 2hrs

Hmm... I just wrote this code, and I am not confident in anyway that this is the proper way to do what your asking(your first question).. its kinda cheap but it works