Compilare: user.cpp: In function ‘int main()’: user.cpp:54:42: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (!st.size() || prio[str[i]] > prio[st.top()]) { ^ user.cpp:54:59: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (!st.size() || prio[str[i]] > prio[st.top()]) { ^ user.cpp:58:50: warning: array subscript has type ‘char’ [-Wchar-subscripts] while (st.size() && prio[st.top()] >= prio[str[i]]) { ^ user.cpp:58:66: warning: array subscript has type ‘char’ [-Wchar-subscripts] while (st.size() && prio[st.top()] >= prio[str[i]]) { ^ user.cpp:88:25: warning: ‘res’ may be used uninitialized in this function [-Wmaybe-uninitialized] int nr1,nr2,res; ^