isPrime test

gistfile1.txt

public static Boolean isPrime(int num){ //method signature. returns Boolean, true if number isPrime, false if not
    if(num==2){ //for case num=2, function returns true. detailed explanation underneath
      return(true);
    }
    for(int i=2;i<=(int)Math.sqrt(num)+1;i++){ //loops through 2 to sqrt(num). All you need to check- efficient
      if(num%i==0){ //if a divisor is found, its not prime. returns false
        return(false);
      }
    }
    return(true); //if all cases don't divide num, it is prime.
  }