How do I open all txt files from a folder?

Question

I am trying to open all text files in the same folder as my main.cpp. How do I go about doing it?

file.open(".txt");

I tried doing this, I tried using *, tried using modulo, but none of it works. Help is appreciated, thank you.

Other question is asking how to get a list of files. I'm asking how to open them. I don't want to list them.

I'm curious as to how you expect `file` to behave if it could open multiple files simultaneously with the same stream. — François Andrieux, May 26 '17 at 19:02
Hint:you first figure the names of all files then you open each one by one. — GhostCat, May 26 '17 at 19:03
The figuring out of what's in the directory is the tricky bit (at least until `filesystem` comes online). What OS are you targeting? — user4581301, May 26 '17 at 19:06
Also read up on "Working Directory". Your program doesn't always run from where you think it does. — user4581301, May 26 '17 at 19:08

eerorika · Answer 1 · 2017-05-26T19:11:01.863

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There is no standard interface for listing files in a directory or matching them against a glob in C++.

You have to depend on a platform specific API to achieve this. To figure out which one, you have to first figure out what system you are programming for.

The upcoming C++17 standard will have an API for listing files in a directory, and it already exists as an optional TS. There is no globbing functionality however. As an alternative, wild card matching can be implemented with regular expressions.

edited May 26 '17 at 19:11

answered May 26 '17 at 19:05

eerorika

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Could you give me a link to a tutorial using the new C++17 standard? – belgarion May 26 '17 at 19:18
@belgarion I haven't come across any. I wouldn't be surprised if some exist, though. – eerorika May 26 '17 at 19:25

score 1 · Answer 2 · answered May 26 '17 at 19:06

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I don't think something like that is possible in cpp. Each file object is opens a single file with the path specified. If you want to open all the files in the folder I'd suggest you list the files in the directory and iteratively open all the required files.

the std::filesystem::directory_iterator(path) returns an iterator that you can use to select the respective file and then open them

answered May 26 '17 at 19:06

morfindel

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Once I have the list of text files, how would I, for example, grab the name of the first file to read it? – belgarion May 26 '17 at 19:21
Yup. You would iterate through all the files and then read them as you have mentioned above using `file.open()` – morfindel May 27 '17 at 12:00

How do I open all txt files from a folder?

2 Answers2