Arrays Test Part 2

Last updated almost 2 years ago

2 questions

Arrays Test Part 2

Last updated almost 2 years ago

2 questions

ARRAY TEST FREE RESPONSE  -  A
The following Numbers class will be used to analyze and retrieve sets of numbers.
public class Numbers
{
    /**  @param num is a positive non-decimal value
    *    Precondition : num >= 0
    *   @return true if the sum of the digit divisors of num is odd
         @return false if the sum of the digit divisors of num is even
    */
  public static boolean isGoofy(int num)
  {
            /* to be implemented in part(a)  */
  }

     /* @param count is a positive non-decimal value
     *    Precondition : count > 0
     *   @return an array containing count Goofy numbers
     */
   public static int[] getSomeGoofyNumbers(int count)
   {
             /* to be implemented in part(b)  */
   }
   // There may be variables / fields, constructors, and methods that are not shown.
}

A. Write the Numbers method isGoofy(), as started below. isGoofy() will receive an integer and determine if that integer is goofy or not goofy.

A goofy number is any number that has a sum of its digit divisors that is odd. The sum of the digit divisors must be greater than zero.

The number 12 has 2 digits – 1 and 2. The number 123 has 3 digits - 1,2, and 3.

The number 26 has 2 digits – 2 and 6. The number 26 is only divisible by 2.

The call isGoofy(12) would return true as 12 has a digit divisor sum of 3 – [1,2] which is odd.
The call isGoofy(15) would return false as 15 has a digit divisor sum of 6 – [1,5] which is even.
The call isGoofy(26) would return false as 26 has a digit divisor sum of 2 – [2] which is even. The call isGoofy(271) would return true as 271 has a digit divisor sum of 1 – [1] which is odd.
The call isGoofy(1234) would return true as 1234 has a digit divisor sum of 3 – [1,2] which is odd.

/** @param num is a positive non-decimal value
* Precondition : num >= 0
* @return true if the sum of the digits of num is odd
@return false if the sum of the digits of num is even
*/
public static boolean isGoofy(int num)
{
//code goes here
}

B. Write the Numbers method getSomeGoofyNumbers(), as started below. getSomeGoofyNumbers() will receive a count of how many Goofy numbers to return.
The call getSomeGoofyNumbers(3) would return [1, 3, 5].
The call getSomeGoofyNumbers(15) would
return [1, 3, 5, 7, 9, 10, 12, 13, 14, 16, 17, 18, 19, 21, 25].

You must call the method from part a, assuming the method works as specified regardless of what you wrote. /* @param count is a positive non-decimal value
* Precondition : stop > 0
* @return an array containing count Goofy numbers
*/
public static int[] getSomeGoofyNumbers(int count)
{
//code goes here
}