Compilare: user.cpp: In function ‘int main()’: user.cpp:38:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=1;j<A.size();++j) ^ user.cpp:40:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(A[i]==A[j] && j<A.size()) ^ user.cpp:52:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=A.size();++i) ^