"Quick judgment primes, 10^9"

See a very god template, specifically what meaning still do not understand, first horse to study again ~

1 BOOLPrime (Long Longnum)2 {  3     if(num = =2|| num = =3|| num = =5)  4         return true; 5     if(num%2==0|| Num%3==0|| Num%5==0|| num = =1)  6         return false; 7   8     Long Longc =7; 9     intMAXC = (int) (sqrt (num)); Ten      while(c <=maxc) One     {   A         if(num% c = =0)   -             return false;  -c + =4;  the         if(num% c = =0)   -             return false;  -c + =2;  -         if(num% c = =0)   +             return false;  -c + =4;  +         if(num% c = =0)   A             return false;  atc + =2;  -         if(num% c = =0)   -             return false;  -c + =4;  -         if(num% c = =0)   -             return false;  inc + =6;  -         if(num% c = =0)   to             return false;  +c + =2;  -         if(num% c = =0)   the             return false;  *c + =6;  $     }  Panax Notoginseng     return true;  -}

"Quick judgment primes, 10^9"