Compilare: main.cpp: In function 'int main()': main.cpp:14:11: warning: array subscript has type 'char' [-Wchar-subscripts] 14 | f[ s[0] ] = 1; | ~~~^ main.cpp:17:14: warning: array subscript has type 'char' [-Wchar-subscripts] 17 | f[s[i]]++; | ~~~^ main.cpp:18:18: warning: array subscript has type 'char' [-Wchar-subscripts] 18 | if (f[s[i]] == 1) | ~~~^ main.cpp:21:18: warning: array subscript has type 'char' [-Wchar-subscripts] 21 | f[s[p]]--; | ~~~^ main.cpp:22:22: warning: array subscript has type 'char' [-Wchar-subscripts] 22 | if (f[s[p]] == 0) | ~~~^