Compilare: In file included from /usr/include/c++/3.3/backward/fstream.h:31, from user.cpp:3: /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 `void invers(char*, char*)': user.cpp:13: warning: comparison between signed and unsigned integer expressions user.cpp:15: warning: converting to non-pointer type `char' from NULL user.cpp: In function `int main()': user.cpp:130: warning: unused variable `nod*q' user.cpp:132: warning: unused variable `int k' user.cpp:137: warning: unused variable `char sir[60]' user.cpp:167:2: warning: no newline at end of file