Compilare: main.cpp: In function 'void Do()': main.cpp:39:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < v.size() - 1; ++i ) ~~^~~~~~~~~~~~~~ main.cpp:46:30: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized] fout << x << ' ' << y << '\n'; ^~~~ main.cpp:46:18: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized] fout << x << ' ' << y << '\n'; ^~~