Compilare: user.cpp: In function ‘void citire()’: user.cpp:18:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<s.length();i++) ^ user.cpp: In function ‘void rezolvare()’: user.cpp:27:58: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(!S.empty() && a[i]>S.top() && M-S.size()<N-i ){ ^ user.cpp:35:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(S.size()<M) ^