Question

Lab Goal :   This lab was designed to teach you how to use while and do while loops.

Lab Description :   A perfect number is any number that is equal to the sum of its divisors. 6 is perfect because it has divisors 1, 2, and 3 which sum to 6.   Determine if the provided numbers are perfect. Use mod (%) to find divisors.

Files Needed :: Perfect.java PerfectRunner.java

Sample Data :

496

45

6

14

8128

1245

33

28

27

33550336

Sample Output :

496 is perfect.

45 is not perfect.

6 is perfect.

14 is not perfect.

8128 is perfect.

1245 is not perfect.

33 is not perfect.

28 is perfect.

27 is not perfect.

33550336 is perfect.

public class Perfect

{

   private int number;

      //add constructors

      //add a set method

      public boolean isPerfect()

      {

      }

      //add a toString - should display the number and either is or is not perfect

     

}

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. If not, PLEASE let me know before you rate, I’ll help you fix whatever issues. Thanks

//Perfect.java

public class Perfect

{

      private int number;

      // constructor taking value for number

      public Perfect(int number) {

            this.number = number;

      }

      // set method for number

      public void setNumber(int number) {

            this.number = number;

      }

      // returns true if number is perfect, else false

      public boolean isPerfect() {

            // initializing a variable to keep the sum of factors

            int factors_sum = 0;

            // starting with i=1

            int i = 1;

            // looping as long as i is less than or equal to number/2

            while (i <= number / 2) {

                  // if i divides number evenly, adding i to factors sum

                  if (number % i == 0) {

                        factors_sum += i;

                  }

                  // updating i

                  i++;

            }

            //returns true if factors sum equals number after the loop

            return factors_sum == number;

      }

      // add a toString - should display the number and either is or is not

      // perfect

      @Override

      public String toString() {

            if (isPerfect()) {

                  return number + " is perfect.";

            } else {

                  return number + " is not perfect.";

            }

      }

}

//PerfectRunner.java

import java.util.Scanner;

public class PerfectRunner {

      public static void main(String[] args) {

            // scanner to read user input

            Scanner sc = new Scanner(System.in);

            // looping as long as there are more integers in input. If you are

            // manually entering input values, try entering one value at a time and

            // press ctrl+Z or ctrl+D to trigger end of file/input.

            while (sc.hasNextInt()) {

                  // reading next integer

                  int n = sc.nextInt();

                  // creating a Perfect object

                  Perfect perfect = new Perfect(n);

                  // invoking toString() method, displaying the result

                  System.out.println(perfect);

            }

      }

}

/*OUTPUT for the given input in question*/

496 is perfect.

45 is not perfect.

6 is perfect.

14 is not perfect.

8128 is perfect.

1245 is not perfect.

33 is not perfect.

28 is perfect.

27 is not perfect.

33550336 is perfect.