Is there any way to open files which have common name beginning without specifying their full names and amount? They should be open one by one, not all at once. For example, I have files: certainstr_123.txt, certainstr_5329764.txt, certainstr_1323852.txt.
Or, maybe, it can be more easily done in some another language? Thank you.
C++ doesn't define a standard way for listing files in that way.
The best cross platform approach is to use a library such as the boost filesystem module. I don't think boost::filesystem has wildcard search, you have to filter files yourself but it isn't difficult.
You could use regular expressions, like in the other answer (it's the perfect-fit solution).
Probably it could be enough to check file extension (i->path().extension()) and filename starting with "certainstr_" (boost::starts_with or std::string::substr).
If you choose C++11 standard regex library make sure to have a recent libstdc++.
There are a lot of system specific functions. E.g. see:
for some Unix/Windows examples.
You could also try something like (Windows):
std::system("dir /b certainstr_*.txt > list.txt");
or (Unix):
std::system("ls -m1 certainstr_*.txt > list.txt");
parsing the list.txt output file (of course this is a hack).
Anyway, depending on your needs, Python-based (or script-based) solutions could be simpler (see also How to list all files of a directory?):
[glob.glob('certainstr_*.txt')][3]
or also:
files = [f for f in os.listdir('.') if re.match(r'certainstr_\d+.txt', f)]
This is the Python equivalent of https://stackoverflow.com/a/26585425/3235496
I suggest just using a regular expression. Pseudo code:
boost::regex reg("^certainstr_\\d+.txt$");
for(recursive_directory_iterator it("."); it != recursive_directory_iterator(); ++it)
{
if(boost::regex_search(it->string(), reg))
{
cout << *it << endl;
}
}