Compilare: In file included from /usr/include/c++/3.3/backward/fstream.h:31, from user.cpp:1: /usr/include/c++/3.3/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 <sstream> instead of the deprecated header <strstream.h>. To disable this warning use -Wno-deprecated. user.cpp: In function `int valid()': user.cpp:7: warning: `int nr' might be used uninitialized in this function user.cpp:27:10: warning: multi-character character constant user.cpp: In function `int main()': user.cpp:15: warning: `int s' might be used uninitialized in this function user.cpp:40:11: warning: no newline at end of file