Compilare: user.cpp: In function ‘int main()’: user.cpp:79:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ninjago.in","r",stdin); ^ user.cpp:80:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ninjago.out","w",stdout); ^ user.cpp:82:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&tip,&n,&m); ^ user.cpp:87:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d ",&a,&b); ^ user.cpp:88:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/cckyqeUh.o: In function `main': user.cpp:(.text.startup+0xc6): warning: the `gets' function is dangerous and should not be used.