Thread: Help Reading a file...

Hello people, Im new to this forum, but just from reading posts I've learned a lot.
I've got a quick question:


So I want to create a file that goes like:
In a file called Users
<md>
<id_user>id number of the user</id_user>
<name>name of the user</name>
<pass>password of the user</pass>
<status>user status(active or non-active)</status>
</md>
//*Uhm I dont know what would be easier, creating a file for each user or just create one big file with all the users..*///
Id like to know how to read just something specific from that file, for example; if I want to read the name of the user without the <> parameters how could I do that and print it on the screen?
Please I'd appreciate it very much if you could help out
thanks

Welcome to the forum, RoRo!

What I believe you want to do is:

1) input each line of the text file, and in that line, remove the <> kind of stuff

2) you want to use a struct (a record), with members for the various parts dealing with each entry (members of the struct, or fields in the record).

3) and put your cleaned up data into said struct.

4) then write out the data as a struct. That will allow it to be efficiently dealt with in the future.

The alternative would be a simple text file with say, each line of text, having the same format:

name
handle
url
sex

or

name, handle, url, sex

This latter has more flexibility, but using struct with members, eases some tasks dealing with the data, greatly - primarily by keeping the data organized better.

One file is preferable.

You basically want an XML data file/files. Personally I would recommend one file with several users, especially if you expect there to be more than a few users. There is a library called 'expat' (The Expat XML Parser) that helps you do XML parsing in C, however, it can be a bit tricky, especially if you're not familiar or comfortable with function pointers.

If you don't really need the structure of XML (I don't think you do), you could try a slightly simpler format, such as CSV: Comma-separated values - Wikipedia, the free encyclopedia. This is actually closer to the format of the password and shadow files that contain similar info on Unix/Linux systems.

Lastly, depending on the end goal of your program, there are languages that will make processing such files (XML or CSV or whatever) much, much easier. PHP certainly comes to mind, there may be others, but I speak about as many computer languages as I do human, which is to say about 1.5.

You may also want to consider how often this data is likely to change. If it's going to change often, by adding, deleting and modifying user entries, you may want to consider a database like mysql, postgresql, etc. instead of a flat text file, as these manipulations will get very tedious and disk-intensive otherwise.

Hey thanks for the warm welcome!
So yeah I was thinking about using structures; but Im not really that familiar with structures(the usage of pointers is still a little blurry :/)..as It seems structures do waste less memory
If I'd choose doing it as structure how should it be started out?
thanks again guys

Code:

#include<stdlib.h>
#include<string.h>
#define TSIZE 50

struct Medico
{
  int Id_Doc[TSIZE];
  char Nombre[TSIZE];
  char Especialidad[TSIZE];
  char Estado[TSIZE];
 struct Medico*next;
};


int main(void)
{
   struct Medico * head = NULL;
   struct Medico * prev, * current;
   char input[TSIZE];
   puts("Que tal nuevo usuario, porfavor dame tu nombre ");
   while (gets(input) != NULL && input[0] != '\0')
     {
       current = (struct Medico *) malloc(sizeof(struct Medico));
       if (head == NULL)
	 
	 head = current;
	 
       else
	 
	   prev->next = NULL;
	   strcpy(current->Nombre, input);
	   puts("Dame tu Especialidad");
	   scanf("%d", &current->Especialidad);
	 
	   while(getchar() != '\n')
	     continue;
	   puts("Quiere registrar a alguien mas? En ese caso deme su nombre, si no dejar en blanco y presionar enter");
	   prev=current;
     }

   if(head==NULL)
     printf("No data entered. ");
   current = head;
   while(current!=NULL)
     {
       printf("Doctor: %s Especialidad: %s ", current->Nombre, current->Especialidad);
       current=current->next;
     }
   current=head;
   while (current !=NULL)
     {
       free(current);
       current=current->next;
     }
   printf("Bye!\n");
   return 0;
   }

Thats the code I've got so far just to ask Name and Specialty for a doctor(for example)
Id_Doc = accnum
nombre=name
especialidad=specialty
estado=status
So im just asking for name and specialty, how could I make the terminal ask for the rest of the arguments...?

oh and back to files.
what would the parameters be if I have a file.txt

<md>
<id_user>0001</id_user>
<name>John Fitzpatrick</name>
<pass>123abc</pass>
<status>Active</status>
</md>

How could I make the restriction to read what is just between <name></name> parameters? and how could I create a counter that each time a user registers it goes adds up 1, so next user should be 0002?

Hahaha^^thanks for the help