Compilare: user.cpp: In function ‘int main()’: user.cpp:46:13: warning: array subscript has type ‘char’ [-Wchar-subscripts] cache[*ptr]++; ^ user.cpp:55:18: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (!cache[*ptr]) ^ user.cpp:76:54: warning: array subscript has type ‘char’ [-Wchar-subscripts] while (ptr < b + len_b && local_uses < cache[*ptr2]) ^ user.cpp:35:21: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(a, 250000, f); ^ user.cpp:36:21: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(b, 250000, f); ^