import java.util.Scanner;
public class PerfectNumbers
{
public static boolean isPerfect(int a)
{
int n = a;
int sum = 0;
boolean perfect;
while (n-- >1)
{if(a%n==0)
sum = sum + n;
}
if (sum==a)
{
perfect = true;
}
else
{
perfect = false;
}
return perfect;
}
public static void main(String[] args)
{
Scanner stdin = new Scanner(System.in);
System.out.println("Enter the number up to which you would like to look for perfect numbers:");
int i = stdin.nextInt();
String factors = "";
while (i>0)
{
if (PerfectNumbers.isPerfect(i)==true)
{int w = i-1;
while (w-- >1)
{if(i%w==0)
factors = factors + " " + Integer.toString(w);
}
System.out.println(i + " is a perfect number it's factors are: " + factors);
}
i = i-1;
}
}
}
I think you need to understand the difference between : if and while
and concept of variable scope
Thank you
All the best...
import java.util.Scanner;
public class PerfectNumbers
{
public static boolean isPerfect(int a)
{
int n = a-1;
int sum = 0;
boolean perfect;
while (a%n==0)
{
if (n!=1)
{
sum = sum + n + (a/n);
}
else
{
sum = sum + n;
}
}
sum++;
if (sum==a)
{
perfect = true;
}
else
{
perfect = false;
}
return perfect;
}
public static void main(String[] args)
{
Scanner stdin = new Scanner(System.in);
System.out.print("Enter the number up to which you would like to look for perfect numbers:");
int i = stdin.nextInt();
int w = i-1;
String factors = null;
while (i>0)
{
if (PerfectNumbers.isPerfect(i)==true)
{
while (i%w==0)
{
factors = factors + " " + Integer.toString(w);
w = w-1;
}
System.out.print(i + " is a perfect number it's factors are: " + factors);
}
i = i-1;
}
}
}
this was the goal:
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.
Sample Output:
Enter the number up to which you would like to look for perfect numbers:Looking for perfect numbers from 1 to 1000
6 is a perfect number it's factors are: 1 2 3
28 is a perfect number it's factors are: 1 2 4 7 14
496 is a perfect number it's factors are: 1 2 4 8 16 31 62 124 248
Thanks in advance
