Compilare: user.cpp: In function ‘int main()’: user.cpp:14:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;(1<<i)<=a;i++) ^ user.cpp:7:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("classictask.in","r",stdin); ^ user.cpp:8:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("classictask.out","w",stdout); ^ user.cpp:9:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lli %lli %lli",&a,&b,&c); ^