Compilare: main.cpp: In function 'int main()': main.cpp:51:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++){ ~^~~~~~~~~ main.cpp:53:20: warning: array subscript has type 'char' [-Wchar-subscripts] ok[s[i]]=true; ^ main.cpp:54:19: warning: array subscript has type 'char' [-Wchar-subscripts] v[s[i]]++; ^ main.cpp:61:47: warning: array subscript is above array bounds [-Warray-bounds] cout<<char(i+'a')<<" "<<v[i+'a']<<'\n'; ^~~~