Compilare: user.cpp: In function ‘void Write()’: user.cpp:58:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i< sol.size();i++,fo<<'\n') ^ user.cpp:59:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j< sol[i].size();j++) ^ user.cpp: In function ‘void Write_Sol()’: user.cpp:66:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i< sol.size()-1;i++,fo<<'\n') ^