Compilare: user.cpp: In function ‘int main()’: user.cpp:13:28: warning: suggest parentheses around ‘+’ inside ‘<<’ [-Wparentheses] for(j=((i*i)<<1+(i<<1)); (j<<1)<n ; j+=(i<<1)+1) ^ user.cpp:7:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ciur.in","r",stdin); ^ user.cpp:8:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ciur.out","w",stdout); ^ user.cpp:9:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^