highest perfect number 100000000 in java

[Melvin Beverwijk]

I need a java code that will give me the highest perfect number under 100.000.000

I have done everything I can but I still don't know. I searched the internet but they only go up to 1000.

Help me please

[Praetor]

post the code that you have done so far and we gladly help you because if you expect people to spoon feed with code then forget it.

[Melvin Beverwijk]

package toetsen;

 

public class Toets {

public static int checkNumber(long num)

{

  long sum = 0;

  for(long i = 1; i < num; i++)

  if(num % i == 0)

    sum += i;

  if(sum == num)

  return 1;

  else

  return 0;

}

 

public static long perfectNumbers(int n)

{

  long num = 6;

  while(num <= n)

  {

  if(checkNumber(num) == 1)

    System.out.println(num+" is perfect number");

  num+=2;

  }

  return num;

}

 

public static void main(String[] arg)

{

  perfectNumbers(100000000);

}

}

 

 

 

it should work. but it has to be faster than a minute

[spacer]

Can't you just use the equation found here in a loop which increases "p" until the outcome is greater than 100,000,000 and then take the previous result?

[Melvin Beverwijk]

I'm new to java so I don't know how to code that to java

[+virtorio MVC]

1. Use a loop to count backwards your highest number - n.

2. Use checkNumber() to see if the value is a perfect number

3. If it is, return the value

4. Print result

 

Psuedo code:

 

function findPerfectNumber(n)

  for i = n, counting down to 0

    if checkNumber(i) is true then

      return i

 

function main

  perfectNumber = findPerfectNumber(100000000);

  print "Highest perfect number is " + perfectNumber

[Praetor]

 

1. Use a loop to count backwards your highest number - n.

2. Use checkNumber() to see if the value is a perfect number

3. If it is, return the value

4. Print result

 

Psuedo code:

 

function findPerfectNumber(n)
  for i = n, counting down to 0
    if checkNumber(i) is true then
      return i
 
function main
  perfectNumber = findPerfectNumber(100000000);
  print "Highest perfect number is " + perfectNumber

 

 

this does seem the best approach, since the OP wants the highest perfect number under a given limit; the OPs code does the opposite and takes longer to get and not only that but it collects all the numbers, which isn't the objective.

[riahc3]

BTW, if you are looking for the highest (biggest) number, Is there a reason you do not choose "long"?

[Andre S. Veteran]

I'm new to java so I don't know how to code that to java

Then your issue is not how to find the highest perfect number, but how to code in Java. You should look into Java tutorials to learn the basics of the language.

[riahc3]

Then your issue is not how to find the highest perfect number, but how to code in Java. You should look into Java tutorials to learn the basics of the language.

:no: