Java – Example – Finding Abundant Numbers

Problem Statement:

Find the abundant integers and number of abundant integers from a given positive integer ‘a’ to a given positive integer ‘b’ where b > a.

Solution:

File Name: Abundant.java

import java.io.*;

public class Abundance {
  static int count = 0;
  public static void main(String[] args) {
    int min = Integer.parseInt(getUserInput("Number from which 
      abundant numbers have to printed: "));
    int max = Integer.parseInt(getUserInput("Number upto which 
      abundant numbers have to printed: "));
    for (int i = min; i <= max; i++) { 
      if (sumOfFactors(i) > i) { System.out.println(i); count++; }
    }
    System.out.println("Number of abundant numbers found: " + count);
  }

  public static String getUserInput (String prompt) {
    String inputLine = null;
    System.out.print(prompt + " ");
    try {
      BufferedReader is = new BufferedReader (new 
        InputStreamReader(System.in));
      inputLine = is.readLine();
      if (inputLine.length() == 0) return null;
    } catch (IOException e) {
      System.out.println("IOException" + e);
    }
    return inputLine;
  }

  public static int sumOfFactors (int i) {
    int sum = 0;
    for (int j = 1; j <= i/2; j++) {
      if (i % j == 0) { sum += j; } 
    }
    return sum; 
  }
}

Exercise:

Solve the above problem yourself. See if you can understand the above solution yourself.