Compilare: user.cpp: In function ‘int ciur()’: user.cpp:10:23: warning: suggest parentheses around ‘+’ inside ‘<<’ [-Wparentheses] for (i=1;((i*i)<<1+(i<<1))<=n;++i) ^ user.cpp:11:29: warning: suggest parentheses around comparison in operand of ‘&’ [-Wparentheses] if (pm[i>>3]&(1<<(i&7))==0) ^ user.cpp:13:26: warning: suggest parentheses around ‘+’ inside ‘<<’ [-Wparentheses] for (j=((i*i)<<1+(i<<1));(j<<1)+1<=n;j+=(i<<n)+1) ^ user.cpp: In function ‘int main()’: user.cpp:26:33: 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:27:35: 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:29:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^