Compilare: main.cpp: In function 'bool IDK(char, char, char, char)': main.cpp:12:8: warning: array subscript has type 'char' [-Wchar-subscripts] f[a]++; ^ main.cpp:13:8: warning: array subscript has type 'char' [-Wchar-subscripts] f[b]++; ^ main.cpp:14:8: warning: array subscript has type 'char' [-Wchar-subscripts] f[c]++; ^ main.cpp:15:8: warning: array subscript has type 'char' [-Wchar-subscripts] f[d]++; ^ main.cpp: In function 'int main()': main.cpp:24:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < chei.length() - 1; ++i) ~~^~~~~~~~~~~~~~~~~~~ main.cpp:26:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = i + 1; j < chei.length(); ++j) ~~^~~~~~~~~~~~~~~ main.cpp:32:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j + 1 == chei.length()) v22 = chei[0]; ~~~~~~^~~~~~~~~~~~~~~~