Compilare: main.c: In function 'main': main.c:7:20: warning: suggest parentheses around '+' inside '<<' [-Wparentheses] for(i=1;((i*i)<<1)+i<<1<=n;i++) ~~~~~~~~~~^~ main.c:9:23: warning: suggest parentheses around '+' inside '<<' [-Wparentheses] for(j=((i*i)<<1)+i<<1;(j<<1)+1<=n;j+=(i<<1)+1) ~~~~~~~~~~^~ main.c:6:2: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("ciur.in","r",stdin),freopen("ciur.out","w",stdout),scanf("%d",&n); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:6:31: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("ciur.in","r",stdin),freopen("ciur.out","w",stdout),scanf("%d",&n); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:6:62: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] freopen("ciur.in","r",stdin),freopen("ciur.out","w",stdout),scanf("%d",&n); ^~~~~~~~~~~~~~