xcode - Open method opens files with full path only C++ -

file opens if write full path (full-path/roots.txt). file fails open if write filename (roots.txt)

and yet, roots.txt in same folder main.cpp. there settings should check on xcode?

here's code:

    string line; ifstream infile; infile.clear(); // infile.open("roots.txt"); infile.open("/users/programming/c++/roots/roots.txt"); if (infile.fail()) cout << "could not open file: " << strerror(errno); getline(infile, line); cout << line; 

if works when attempt open file absolute path , fails filename, relative path incorrect. ensure roots.txt placed in current working directory. getcwd function declared in unistd.h.