Question

An integer number is said to be a perfect number if its factors, including 1 (but not the number itself), sum to the number. For example, 6 is a perfect number, because 6 = 1+2+3. Write a method isPerfect that determines if parameter number is a perfect number. Use this method in a test program to display all the perfect numbers between 1 and 1000. Display the factors of each perfect number to confirm that the number is indeed perfect.

Answer 1

Thanks for the question, there are 4 perfect numbers between 1 and 1000. here is the code and the output of all the 4 perfect numbers and its factor.

Let me know for any help with any other questions.


Thank You !
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public class PerfectNum {

    public static boolean isPefect(int num) {

        int factorTotal = 0;
        for (int factor = 1; factor <= (num + 1) / 2; factor++) {
            if (num % factor == 0) factorTotal += factor;
        }
        return factorTotal == num;
    }

    public static void main(String[] args) {

        for (int num = 1; num <= 1000; num++) {
            if (isPefect(num)) {

                System.out.print("Perfect Number: " + num + " =  Factors ( ");
                for (int factor = 1; factor <= (num + 1) / 2; factor++) {
                    if (num % factor == 0)
                        System.out.print(factor + " ");
                }
                System.out.println(") ");
            }

        }

    }
}

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