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.gtupapers;
public class ArmstrongNumber {
public static void main(String[] args) {
int inputArmstrongNumber = 153; //Input number to check armstrong
int tempNumber, digit, digitCubeSum = 0;
tempNumber = inputArmstrongNumber;
while (tempNumber != 0)
{
/* On each iteration, remainder is powered by thetempNumber of digits n
*/
System.out.println("Current Number is "+tempNumber);
digit =tempNumber % 10;
System.out.println("Current Digit is "+digit);
//sum of cubes of each digits is equal to thetempNumber itself
digitCubeSum = digitCubeSum + digit*digit*digit;
System.out.println("Current digitCubeSum is "+digitCubeSum);
tempNumber /= 10;
}
//check giventempNumber and digitCubeSum is equal to or not
if(digitCubeSum == inputArmstrongNumber)
System.out.println(inputArmstrongNumber + " is an Armstrong Number");
else
System.out.println(inputArmstrongNumber + " is not an Armstrong Number");
}
}
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.gtupapers;
public class ArmstrongNumber {
public static void main(String[] args) {
int tempNumber, digit, digitCubeSum;
for (int inputArmstrongNumber = 0; inputArmstrongNumber < 1000; inputArmstrongNumber++) {
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;
tempNumber /= 10;
}
//check giventempNumber and digitCubeSum is equal to or not
if (digitCubeSum == inputArmstrongNumber)
System.out.println(inputArmstrongNumber + " is an Armstrong Number");
}
}
} 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
