Compilare: user.cpp: In function ‘int main()’: user.cpp:15:47: warning: array subscript has type ‘char’ [-Wchar-subscripts] for (int i = 1;s[i];++i) ++a[s[i]-='a']; ^ user.cpp:17:47: warning: array subscript has type ‘char’ [-Wchar-subscripts] for (int i = 1;s[i];++i) ++b[s[i]-='a']; ^ user.cpp:8:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("joben.in","r",stdin); ^ user.cpp:10:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:13:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s",s+1); ^ user.cpp:16:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s",s+1); ^