Compilare: In file included from /usr/include/c++/4.2/backward/hash_map.h:59, from user.cpp:7: /usr/include/c++/4.2/backward/backward_warning.h:32:2: warning: #warning This file includes at least one deprecated or antiquated header. Please consider using one of the 32 headers found in section 17.4.1.2 of the C++ standard. Examples include substituting the <X> header for the <X.h> header for C++ includes, or <iostream> instead of the deprecated header <iostream.h>. To disable this warning use -Wno-deprecated. user.cpp: In function 'bool operator<(const nod&, const nod&)': user.cpp:17: warning: control reaches end of non-void function /tmp/cc8QlckJ.o: In function `main': user.cpp:(.text+0x178): warning: the `gets' function is dangerous and should not be used.