Kotlin Program to Check Armstrong Number between Two Integers

In this article, we will understand how to display the Armstrong numbers between the given two numbers in Kotlin. An Armstrong number is a number that is equal to the sum of the cubes of its own digits. For example, 153 is

153 = (1)3 + (5)3 + (3)3

Below is a demonstration of the same

Suppose our input is

1 & 500

The desired output would be

The Armstrong numbers between 1 and 500 are 2, 3, 4, 5, 6, 7, 8, 9, 153, 370, 371, 407

Algorithm

• Step 1 − Start

• Step 2 − Declare four integers: inputLow, inputHigh, originalNumber and myResult

• Step 3 − Define inputLow and inputHigh values

• Step 4 − Read the values

• Step 5 − Run a for loop to generate Armstrong numbers using %, / and * operator

• Step 6 − Divide by 10 and get remainder for ‘originalNumber’.

• Step 7 − Multiply ‘remainder’ thrice, and add to ‘myResult’, and make that the current ‘myResult’.

• Step 8 − Divide ‘originalNumber’ by 10, and make that the current ‘originalNumber’.

• Step 9 − Display the result

• Step 10 − Stop

Example 1

In this example, we will check Armstrong Number between two integers in Kotlin. First, declare and set two variables. This is the range within which we will find the Armstrong Numbers −

val inputLow = 1
val inputhigh = 500

Now, use the while loop inside for loop to find the Armstrong numbers in a range

for (number in inputLow + 1..inputhigh - 1) {
   var tempDigits = 0
   var myResult = 0
   var originalNumber = number

   while (originalNumber != 0) {
      originalNumber /= 10
      ++tempDigits
}

originalNumber = number

while (originalNumber != 0) {
   val remainder = originalNumber % 10
   myResult += Math.pow(remainder.toDouble(), tempDigits.toDouble()).toInt()
   originalNumber /= 10
}

Let us now see the complete example to find the Armstrong Numbers

fun main() {
   val inputLow = 1
   val inputhigh = 500
   println("The lower and higher limit are defined as $inputLow and $inputhigh ")
   println("The Armstrong numbers are:")

   for (number in inputLow + 1..inputhigh - 1) {
      var tempDigits = 0
      var myResult = 0
      var originalNumber = number
      
      while (originalNumber != 0) {
         originalNumber /= 10
         ++tempDigits
      }
      originalNumber = number
      
      while (originalNumber != 0) {
         val remainder = originalNumber % 10
         myResult += Math.pow(remainder.toDouble(), tempDigits.toDouble()).toInt()
         originalNumber /= 10
      }

      if (myResult == number)
         print("$number ")
   }
}

Output

The lower and higher limit are defined as 1 and 500
The Armstrong numbers are:
2 3 4 5 6 7 8 9 153 370 371 407

Example 2

In this example, we will get the Armstrong Numbers between two integers

fun main() {
   val inputLow = 1
   val inputhigh = 500
   println("The lower and higher limit are defined as $inputLow and $inputhigh ")
   printArmstrongNumbers(inputLow, inputhigh)
}

fun printArmstrongNumbers(inputLow: Int, inputhigh: Int) {
   println("The Armstrong numbers are:")
   for (number in inputLow + 1..inputhigh - 1) {
      var tempDigits = 0
      var myResult = 0
      var originalNumber = number
      while (originalNumber != 0) {
         originalNumber /= 10
         ++tempDigits
      }
      
      originalNumber = number
      while (originalNumber != 0) {
         val remainder = originalNumber % 10
         myResult += Math.pow(remainder.toDouble(), tempDigits.toDouble()).toInt()
         originalNumber /= 10
      }

      if (myResult == number)
         print("$number ")
   }
}

Output

The lower and higher limit are defined as 1 and 500
The Armstrong numbers are:
2 3 4 5 6 7 8 9 153 370 371 407