Compilare: user.cpp: In function ‘void explore()’: user.cpp:43:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < wall[wallset].size() ;i++){ ^ user.cpp:48:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < wall[wallset].size() ;i++){ ^