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Java Program to Check Armstrong Number

Armstrong Number Program in JAVA

What is Armstrong Number ?

In an Armstrong Number, the sum of power of individual digits is equal to number itself.

In other words the following equation will hold true

xy..z = xn + yn+.....+ zn

n is number of digites in number

For example this is a 3 digit Armstrong number

370 = 33 + 73 + o3
 = 27 + 343 + 0
 = 370

Examples of Armstrong Numbers

 0, 1, 4, 5, 9, 153, 371, 407, 8208, etc.

Let’s write this in a program:

Java Program to check whether a number is Armstrong Number

  • //ChecktempNumber is Armstrong or not using while loop
  •  
  • package com.guru99;
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  • public class ArmstrongNumber {
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  • public static void main(String[] args) {
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  • int inputArmstrongNumber = 153; //Input number to check armstrong
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  • int tempNumber, digit, digitCubeSum = 0;
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  • tempNumber = inputArmstrongNumber;
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  • while (tempNumber != 0)
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  • {
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  • /* On each iteration, remainder is powered by thetempNumber of digits n
  • */
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  • System.out.println(“Current Number is “+tempNumber);
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  • digit =tempNumber % 10;
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  • System.out.println(“Current Digit is “+digit);
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  • //sum of cubes of each digits is equal to thetempNumber itself
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  • digitCubeSum = digitCubeSum + digit*digit*digit;
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  • System.out.println(“Current digitCubeSum is “+digitCubeSum);
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  • tempNumber /= 10;
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  • }
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  • //check giventempNumber and digitCubeSum is equal to or not
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  • if(digitCubeSum == inputArmstrongNumber)
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  • System.out.println(inputArmstrongNumber + ” is an Armstrong Number”);
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  • else
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  • System.out.println(inputArmstrongNumber + ” is not an Armstrong Number”);
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  • }
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  • }

Output

Current Number is 153
Current Digit is 3
Current digitCubeSum is 27
Current Number is 15
Current Digit is 5
Current digitCubeSum is 152
Current Number is 1
Current Digit is 1
Current digitCubeSum is 153
153 is an Armstrong Number

Java Program to Print Armstrong numbers from 0 to 999

  • //ChecktempNumber is Armstrong or not using while loop
  •  
  •  
  • package com.guru99;
  •  
  •  
  •  
  • public class ArmstrongNumber {
  •  
  •  
  •  
  • public static void main(String[] args) {
  •  
  •  
  • int tempNumber, digit, digitCubeSum;
  •  
  •  
  •  
  • for (int inputArmstrongNumber = 0; inputArmstrongNumber < 1000; inputArmstrongNumber++) {
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  • tempNumber = inputArmstrongNumber;
  • digitCubeSum = 0;
  •  
  •  
  • while (tempNumber != 0) {
  •  
  •  
  •  
  • /* On each iteration, remainder is powered by thetempNumber of digits n
  • */
  •  
  •  
  •  
  • digit = tempNumber % 10;
  •  
  •  
  •  
  • //sum of cubes of each digits is equal to thetempNumber itself
  •  
  •  
  • digitCubeSum = digitCubeSum + digit * digit * digit;
  •  
  •  
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  • tempNumber /= 10;
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  • }
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  • //check giventempNumber and digitCubeSum is equal to or not
  •  
  •  
  • if (digitCubeSum == inputArmstrongNumber)
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  •  
  • System.out.println(inputArmstrongNumber + ” is an Armstrong Number”);
  •  
  •  
  •  
  • }
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  •  
  •  
  • }
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  •  
  •  
  • }

Output

0 is an Armstrong Number
1 is an Armstrong Number
153 is an Armstrong Number
370 is an Armstrong Number
371 is an Armstrong Number
407 is an Armstrong Number