Compilare: main.cpp: In function 'int main()': main.cpp:14:18: warning: NULL used in arithmetic [-Wpointer-arith] while (s[n]!=NULL) ^~~~ main.cpp:17:12: warning: array subscript has type 'char' [-Wchar-subscripts] ap[s[1]]++; ^ main.cpp:21:25: warning: array subscript has type 'char' [-Wchar-subscripts] sum=(tot-ap[s[b]])*(n+1-b); ^ main.cpp:22:16: warning: array subscript has type 'char' [-Wchar-subscripts] ap[s[b]]+=b; ^