Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:26:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (stiv.top()<a[i] && dupa[i]>m-stiv.size() && !stiv.empty()) ^ user.cpp:29:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (stiv.size()<m) ^ user.cpp:39:14: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] afis[i+1]=NULL; ^ user.cpp:40:16: error: ‘strrev’ was not declared in this scope strrev(afis); ^