Unable to resolve clang: error: linker command failed with exit code 1

Question

I am trying to implement a basic virtual file system implemented in C++ using this repository https://github.com/dipkakwani/Virtual-file-system

But when I run main.cpp I get following errors :

Undefined symbols for architecture x86_64:
  "filesys::list_files()", referenced from:
      _main in main-2b20bb.o
  "filesys::create_file(char*, char*)", referenced from:
      _main in main-2b20bb.o
  "filesys::delete_file(char*)", referenced from:
      _main in main-2b20bb.o
  "filesys::search_file(char*)", referenced from:
      _main in main-2b20bb.o
  "filesys::search_keyword(char*, char*)", referenced from:
      _main in main-2b20bb.o
  "filesys::show_file_content(char*)", referenced from:
      _main in main-2b20bb.o
  "filesys::filesys(char*)", referenced from:
      _main in main-2b20bb.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Any suggestions why ?

I read the another answers but I want to run this same code without any editing so any ways to get through in mac os ?

It's for my project so can't do much changes to the code that's why I am asking new question and is different from others already had answered as it has to modify the code.

It will be good if you download the repo and run on your system