Getting a directory name from a filename - c++

Question

I have a filename (C:\folder\foo.txt) and I need to retrieve the folder name (C:\folder) in C++. In C# I would do something like this:
string folder = new FileInfo("C:\folder\foo.txt").DirectoryName;
Is there a function that can be used in C++ to extract the path from the filename?

Answer 1

Using Boost.Filesystem:
boost::filesystem::path p("C:\\folder\\foo.txt");
boost::filesystem::path dir = p.parent_path();

Answer 2

Example from http://www.cplusplus.com/reference/string/string/find_last_of/
// string::find_last_of
#include <iostream>
#include <string>
using namespace std;
void SplitFilename (const string& str)
{
size_t found;
cout << "Splitting: " << str << endl;
found=str.find_last_of("/\\");
cout << " folder: " << str.substr(0,found) << endl;
cout << " file: " << str.substr(found+1) << endl;
}
int main ()
{
string str1 ("/usr/bin/man");
string str2 ("c:\\windows\\winhelp.exe");
SplitFilename (str1);
SplitFilename (str2);
return 0;
}

Answer 3

In C++17 there exists a class std::filesystem::path using the method parent_path.
#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;
int main()
{
for(fs::path p : {"/var/tmp/example.txt", "/", "/var/tmp/."})
std::cout << "The parent path of " << p
<< " is " << p.parent_path() << '\n';
}
Possible output:
The parent path of "/var/tmp/example.txt" is "/var/tmp"
The parent path of "/" is ""
The parent path of "/var/tmp/." is "/var/tmp"

Answer 4

There is a standard Windows function for this, PathRemoveFileSpec. If you only support Windows 8 and later, it is highly recommended to use PathCchRemoveFileSpec instead. Among other improvements, it is no longer limited to MAX_PATH (260) characters.

Answer 5

Why does it have to be so complicated?
#include <windows.h>
int main(int argc, char** argv) // argv[0] = C:\dev\test.exe
{
char *p = strrchr(argv[0], '\\');
if(p) p[0] = 0;
printf(argv[0]); // argv[0] = C:\dev
}

Answer 6

auto p = boost::filesystem::path("test/folder/file.txt");
std::cout << p.parent_path() << '\n'; // test/folder
std::cout << p.parent_path().filename() << '\n'; // folder
std::cout << p.filename() << '\n'; // file.txt
You may need p.parent_path().filename() to get name of parent folder.

Answer 7

Use boost::filesystem. It will be incorporated into the next standard anyway so you may as well get used to it.

Answer 8

I'm so surprised no one has mentioned the standard way in Posix
Please use basename / dirname constructs.
man basename

Answer 9

_splitpath is a nice CRT solution.

Answer 10

Standard C++ won't do much for you in this regard, since path names are platform-specific. You can manually parse the string (as in glowcoder's answer), use operating system facilities (e.g. http://msdn.microsoft.com/en-us/library/aa364232(v=VS.85).aspx ), or probably the best approach, you can use a third-party filesystem library like boost::filesystem.

Answer 11

Just use this: ExtractFilePath(your_path_file_name)