- Java Basic Programs
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- Java Add two Numbers
- Java Check Even or Odd
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- Check Reverse equal Original
- Java Fahrenheit to Celsius
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- Java Perfect Number Program
- Java Find Quotient Remainder
- Java Days to Seconds
- Java Count Digits in Number
- Java Binary Number Addition
- Java Discount Program
- Java Compute Courier Charge
- Java Find Telephone Bill
- Java Print ASCII Values
- Java Check Palindrome or Not
- Java Check Armstrong or Not
- Generate Armstrong Numbers
- Add two Numbers using Pointers
- Java Mathematical Programs
- Add Subtract Multiply & Divide
- Java Make Calculator
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- Java Check Leap Year or Not
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- Calculate Average & Percentage
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- Count Positive Negative & Zero
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- Java Pattern of Stars
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- Java Array Programs
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- Two Dimensional Array Program
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- Java Transpose Matrix
- Multiply two Matrices
- Three Dimension Array Program
- Java String Programs
- Java Print String
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- Java Compare two String
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- Delete Vowels from String
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- Java Find Occurrence of a Word
- Occurrence of Each Character
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- Java Count Repeated Characters
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- Java Capitalize Each Word
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- Java Check Anagram or Not
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- Generate Random Numbers
- Java Print Time & Date
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- Java Programming Tutorial
- Java Tutorial
Java Program to Check Armstrong Number or Not
This article covers multiple programs in Java that checks whether a number entered by user at run-time of the program, is an Armstrong number or not.
An Armstrong number is a number that is equal to the sum of its own digits, where each digit raised to the power of number of digit. For example, 153 is an Armstrong number, because:
153 = 13 + 53 + 33 = 1 + 125 + 27 = 153
Some other Armstrong numbers are 1, 2, 3, 4, 5, 6, 7, 8, 9, 370, 371, 407, 1634 etc.
Check Armstrong Number in Java using while Loop
The question is, write a Java program to check whether a number is an Armstrong number or not. The number must be received by user at run-time. The program given below is its answer:
import java.util.Scanner; public class fresherearth { public static void main(String[] args) { int num, temp, totalDigit=0, res=0, rem, pow, i; Scanner scan = new Scanner(System.in); System.out.print("Enter the Number: "); num = scan.nextInt(); temp = num; while(num>0) { num = num/10; totalDigit++; } num = temp; while(num>0) { rem = num%10; pow = 1; i = 0; while(i<totalDigit) { pow = pow*rem; i++; } res = res + pow; num = num/10; } if(res==temp) System.out.println("\nArmstrong Number"); else System.out.println("\nNot an Armstrong Number."); } }
The snapshot given below shows the sample run of above program with user input 407 as number to check whether it is an Armstrong number or not:
The above program can also be written as. This program uses Math.pow() method to directly calculate the value, of a number to the power of another number:
import java.util.Scanner; import java.lang.Math; public class fresherearth { public static void main(String[] args) { int num, temp, totalDigit=0, res=0, rem; Scanner scan = new Scanner(System.in); System.out.print("Enter the Number: "); num = scan.nextInt(); temp = num; while(num>0) { num /= 10; totalDigit++; } num = temp; while(num>0) { rem = num%10; res = res + (int) Math.pow(rem, totalDigit); num /= 10; } if(res==temp) System.out.println("\nArmstrong Number"); else System.out.println("\nNot an Armstrong Number."); } }
The sample run of above program with user input 371 is shown in the snapshot given below:
Check Armstrong Number in Java using for Loop
The previous program, that was created using while loop, can also be created using for loop, as shown here:
import java.util.Scanner; public class fresherearth { public static void main(String[] args) { int num, temp, totalDigit=0, res=0, rem; Scanner scan = new Scanner(System.in); System.out.print("Enter the Number: "); num = scan.nextInt(); for(temp=num; num>0; num /= 10) totalDigit++; for(num=temp; num>0; num /= 10) { rem = num%10; res = res + (int) Math.pow(rem, totalDigit); } if(res==temp) System.out.println("\nArmstrong Number"); else System.out.println("\nNot an Armstrong Number."); } }
Check Armstrong Number in Java - Only for 3-Digit Number
Here is another way, that we can create the same program. But this program is limited to 3-digit number only:
import java.util.Scanner; public class fresherearth { public static void main(String[] args) { int num, temp, res=0, rem; Scanner scan = new Scanner(System.in); System.out.print("Enter the Number: "); num = scan.nextInt(); temp = num; while(temp!=0) { rem = temp%10; res = res + (rem*rem*rem); temp = temp/10; } if(num==res) System.out.println("\nArmstrong Number."); else System.out.println("\nNot an Armstrong Number."); } }
Same Program in Other Languages
- C Check Armstrong Number or Not
- C++ Check Armstrong Number or Not
- Python Check Armstrong Number or Not
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