### 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;

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.guru99;

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
```

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