Compilare: user.cpp: In function ‘int main()’: user.cpp:13:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fr("magicnum.in","r",stdin); ^ user.cpp:14:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fr("magicnum.out","w",stdout); ^ user.cpp:29:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] in("%d %d",&x,&y); ^