How to store name of file in folder to array in c ++ ?

How to store name of file in folder to array in c ++ ?

I am new in c++ . And i want to write a function which takes names from
folder.
for example i have a folder which name is C:\TEST and in this folder i
have lots of text.txt files i want to store all .txt files name in a
string array.
Anybody could help me about this issue.
i tried something like this but i failed
const int arr_size = 10;
some_type src[arr_size];
// ...
some_type dest[arr_size];
std::copy(std::begin(src), std::end(src), std::begin(dest));