Thread: traversing text file

Hi,

I was wondering if anyone has any ideas on how I can establish multiple traversals through an opened text file. That is, can I "getline" at one point in the file, move to another point in the file and get another line, and then go back to the original point? Or do I have to go through the file line by line.

(Hope that made sense)
Thanks for any help!

>> Or do I have to go through the file line by line.

Well, you would basically have to go through the whole file and map out where the line breaks are, and then jump around with seekg to those points. It just seems easier to read the whole file while you're doing this into a more easily managed vector of lines.

Thanks for your help. I'm relatively new to C++ so I was wondering if you could give me some further help. Here's my little dilemma: I have a text file containing a bunch of contacts (addresses, phone numbers, etc.). They are arranged one after another in 'blocks' so that there is at least one blank space between each contact. The problem is, many of them are duplicates. This text file is over 1800 pages so I would like to write a program that finds these duplicates and deletes them (instead of manually going through them myself). Any ideas what approach I might take? Thanks!

Thanks. Where can I learn more about std::set?

What does the text file look like? Like this?

Code:

Name: Batman
Address: Gotham City, Batcave
Phone Number: 123456789

Name: Spiderman
Address: NYC, USA
Phone Number: 987654321

You could read each contact into a Contact object, then insert those Contact objects into a std::set (as Prelude said). Google has plenty of infomration on std::set. Here's the SGI reference page.

Thanks. Yeah, that's kind of how the text file looks, except the contacts are not all of the same format. Some have extra fields, others don't. Would this pose a problem? Also, how would I read each contact into a Contact object?

Originally Posted by AML25

Also, how would I read each contact into a Contact object?

If you're sure that each Contact is separated by an empty line, then I'd do something like this

1. Create a std::map<string,string>.
2. If there's input, read and put everything you see in a std::string until you reach an empty line. If there's no input, goto 6.
3. Parse what you've read and find the name (e.g. batman)
4. If the name already exists in the map, go back to 2. Else add the contactString to the map with the name as the key. E.g.

Code:

m["batman"]=contactString;

5. Go back to 2.
6. stop