Compilare: main.cpp: In function 'void eval(bool)': main.cpp:11:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (pos < s.size() && s[pos] != ')') { ~~~~^~~~~~~~~~ main.cpp:27:21: warning: array subscript has type 'char' [-Wchar-subscripts] --fv[lit]; ^ main.cpp:29:21: warning: array subscript has type 'char' [-Wchar-subscripts] ++fv[lit]; ^ main.cpp: In function 'int main()': main.cpp:39:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.size(); ++i) ~~^~~~~~~~~~ main.cpp:41:24: warning: array subscript has type 'char' [-Wchar-subscripts] exista[s[i]] = true; ^