Compilare: user.cpp: In function ‘int main()’: user.cpp:13:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dstar.in","r",stdin); ^ user.cpp:14:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dstar.out","w",stdout); ^ user.cpp:15:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d\n",&n,&m); ^ user.cpp:16:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:39:14: warning: ‘nr’ may be used uninitialized in this function [-Wmaybe-uninitialized] v[++j]=nr; ^ /tmp/ccqj86et.o: In function `main': user.cpp:(.text.startup+0x7c): warning: the `gets' function is dangerous and should not be used.