Compilare: user.cpp: In function ‘int main()’: user.cpp:16:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(first[s[i]]==INF) ^ user.cpp:17:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] first[s[i]]=i; ^ user.cpp:8:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trompeta.in","r",stdin); ^ user.cpp:9:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trompeta.out","w",stdout); ^ user.cpp:11:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d\n%s",&n,&m,s); ^