Compilare: main.cpp: In function 'int main()': main.cpp:17:24: warning: array subscript has type 'char' [-Wchar-subscripts] else if(!a[s[i]]) ^ main.cpp:18:19: warning: array subscript has type 'char' [-Wchar-subscripts] a[s[i]] = 1, ^ main.cpp:11:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("domenii.in", "r", stdin); ^ main.cpp:12:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("domenii.out", "w", stdout); ^ main.cpp:13:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d ", &n), cin>>s; ^