Armstrong Number in JAVA Program Using For Loop

ByJames Hartman Hours Updated

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 digits 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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