Compilare: user.cpp: In function ‘int main()’: user.cpp:9:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("flori4.in","r",stdin); ^ user.cpp:10:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("flori4.out","w",stdout); ^ user.cpp:8:11: warning: ‘fn’ may be used uninitialized in this function [-Wmaybe-uninitialized] int n,fn,fn_1=2,fn_2=1,i; ^