Compilare: user.cpp: In function ‘int main()’: user.cpp:38:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (stiv.top()<a[i] && dupa[i]>m-stiv.size() && !stiv.empty()) ^ user.cpp:41:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (stiv.size()<m) ^ user.cpp:51:12: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] afis[m]=NULL; ^