Compilare: user.cpp: In function ‘int main()’: user.cpp:9:10: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[s[0]]++; nr++; ^ user.cpp:17:25: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(f[s[j]]==0) nr++; ^ user.cpp:18:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[s[j]]++; ^ user.cpp:23:15: warning: array subscript has type ‘char’ [-Wchar-subscripts] { f[s[i]]--; ^ user.cpp:24:21: warning: array subscript has type ‘char’ [-Wchar-subscripts] nr-=(!f[s[i]]); ^ user.cpp:5:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] { freopen("teatru.in", "r", stdin); ^ user.cpp:6:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("teatru.out", "w", stdout); ^ user.cpp:7:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%s",&n,&k,s); ^