Compilare: main.cpp: In function 'int main()': main.cpp:19:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 19 | for(int i=0; i<line1.length(); i++) { | ~^~~~~~~~~~~~~~~ main.cpp:20:22: warning: array subscript has type 'char' [-Wchar-subscripts] 20 | if(f[line1[i]].ok==0) { | ^ main.cpp:21:23: warning: array subscript has type 'char' [-Wchar-subscripts] 21 | f[line1[i]].ok=1; | ^ main.cpp:22:23: warning: array subscript has type 'char' [-Wchar-subscripts] 22 | f[line1[i]].tw=line2[i]; | ^ main.cpp:24:26: warning: array subscript has type 'char' [-Wchar-subscripts] 24 | if(f[line1[i]].tw!=line2[i]) { | ^