Compilare: main.cpp: In function 'int main()': main.cpp:18:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<strlen(a);i++){ ~^~~~~~~~~~ main.cpp:21:27: warning: array subscript has type 'char' [-Wchar-subscripts] if(change[a[i]] == 0){ ^ main.cpp:22:28: warning: array subscript has type 'char' [-Wchar-subscripts] change[a[i]] = b[i]; ^ main.cpp:25:27: warning: array subscript has type 'char' [-Wchar-subscripts] if(change[a[i]] != 0){ ^ main.cpp:26:31: warning: array subscript has type 'char' [-Wchar-subscripts] if(change[a[i]] != b[i]){ ^ main.cpp:34:27: warning: array subscript has type 'char' [-Wchar-subscripts] if(change[a[i]] != 0){ ^ main.cpp:35:31: warning: array subscript has type 'char' [-Wchar-subscripts] if(change[a[i]] != b[i]){ ^