Compilare: main.cpp: In function 'int main()': main.cpp:35:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < s.size(); i++) ~~^~~~~~~~~~ main.cpp:40:34: warning: array subscript has type 'char' [-Wchar-subscripts] if(!st.empty() && tp[s[i]] == tp[s[st.top()]]) ^ main.cpp:40:53: warning: array subscript has type 'char' [-Wchar-subscripts] if(!st.empty() && tp[s[i]] == tp[s[st.top()]]) ^ main.cpp:54:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < s.size(); i++) ~~^~~~~~~~~~