Compilare: user.cpp: In function ‘int main()’: user.cpp:24:12: warning: array subscript has type ‘char’ [-Wchar-subscripts] ++ f[s[0]]; ^ user.cpp:28:21: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(!(f[s[dr]] ++)) ^ user.cpp:35:25: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(!(-- f[s[st ++]])) ^ user.cpp:15:35: 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:16:37: 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:19:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &N, &C); ^ user.cpp:20:10: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:40:3: warning: ‘i’ may be used uninitialized in this function [-Wmaybe-uninitialized] for(int k = i; k <= j; ++ k) ^ /tmp/ccnJeuZ8.o: In function `main': user.cpp:(.text.startup+0x74): warning: the `gets' function is dangerous and should not be used.