Solution: Find the Largest Number

class MaxNumber {
 public static int findSumOfDigits(int num) {
  int sum = 0;
  while (num != 0) {
   sum = sum + num % 10;
   num = num / 10;
  }
  return sum;
 }
public static void findLargestNumber(int numberOfDigits, int sumOfDigits) {
  int max = 0;
  int startRange = (int) Math.pow(10, (numberOfDigits - 1));
  int endRange = (int) Math.pow(10, numberOfDigits);
  if (sumOfDigits == 0) {
    if (numberOfDigits == 1)
      System.out.println("Largest number is " + 0);
    else
      System.out.println("Largest number is Not possible");
    return;
  }
  
  // sumOfDigits is greater than the maximum possible sum. 
  if (sumOfDigits > 9 * numberOfDigits) {
    System.out.println("Largest number is Not possible");
    return;
  }
  while (startRange < endRange) {
    if (findSumOfDigits(startRange) == sumOfDigits) {
      if (max < startRange)
        max = startRange;
    }
    startRange++;
  }
  System.out.println("Largest number is " + max);
}
}
class Main{
  public static void main(String[] args) {
  int sumOfDigits = 20;
  int numberOfDigits = 3;
  System.out.println("If sum of digits is 20 and number of digits is 3 then ");
  MaxNumber.findLargestNumber(numberOfDigits, sumOfDigits);
  System.out.println();
  //Example 2
  sumOfDigits = 100;
  numberOfDigits = 2;
  System.out.println("If sum of digits is 100 and number of digits is 2 then ");
  MaxNumber.findLargestNumber(numberOfDigits, sumOfDigits);
  
}
}