Compilare: main.cpp: In function 'int main()': main.cpp:16:11: warning: array subscript has type 'char' [-Wchar-subscripts] 16 | fr[s[0]]++; nrc++; | ~~~^ main.cpp:23:21: warning: array subscript has type 'char' [-Wchar-subscripts] 23 | if (fr[s[dr]] == 0) | ~~~~^ main.cpp:25:20: warning: array subscript has type 'char' [-Wchar-subscripts] 25 | fr[s[dr]]++; | ~~~~^ main.cpp:29:20: warning: array subscript has type 'char' [-Wchar-subscripts] 29 | fr[s[dr]]++; | ~~~~^ main.cpp:40:17: warning: array subscript has type 'char' [-Wchar-subscripts] 40 | fr[s[st]]--; | ~~~~^ main.cpp:41:20: warning: array subscript has type 'char' [-Wchar-subscripts] 41 | if(fr[s[st]] == 0){ | ~~~~^