Compilare: user.cpp: In function ‘int main()’: user.cpp:45:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<in.size();i++) ^ user.cpp:65:46: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(!st.empty()&&p[st.top()]>p[in[i]]) ^ user.cpp:65:55: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(!st.empty()&&p[st.top()]>p[in[i]]) ^ user.cpp:37:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j; ^