Compilare: user.cpp: In function ‘int main()’: user.cpp:72:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("fibo4.in","r",stdin); ^ user.cpp:73:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("fibo4.out","w",stdout); ^ user.cpp: In function ‘void define_and_read()’: user.cpp:40:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp: In function ‘void solve()’: user.cpp:53:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%lld",&st,&dr,&k); ^