Compilare: main.cpp: In function 'int main()': main.cpp:15:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s2.size(); ++i) ~~^~~~~~~~~~~ main.cpp:19:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s1.size(); ++i) ~~^~~~~~~~~~~ main.cpp:22:17: warning: array subscript has type 'char' [-Wchar-subscripts] ++fr2[ch]; ^ main.cpp:23:19: warning: array subscript has type 'char' [-Wchar-subscripts] if (fr2[ch] == fr[ch]) ^ main.cpp:23:29: warning: array subscript has type 'char' [-Wchar-subscripts] if (fr2[ch] == fr[ch]) ^