2 Ways To Find Armstrong Number in Java
Let us understand the concept of Armstrong Number in Java programming language and write a Java program to check Armstrong number using a variety of methods.
What is Armstrong Number Series?
An Armstrong integer is the sum of cubes of the individual digits of the integer. If the sum of the digits is equal to the number, then it is an Armstrong Number.
An Armstrong number is similar to a Narcissistic Number. There’s a difference between an Armstrong number and a Narcissistic number.
An Armstrong integer is usually a 3 digit number whereas a narcissistic number which consists of 4 or more than 4 digits, which is also regarded as 4 digit Armstrong Number.
Algorithm For Armstrong Numbers
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | Step 1: Start Step 2: Input num from the user, assign temp = num and sum = 0 Step 3: while(num > 0) do rem = num % 10 sum = sum + (rem * rem * rem) num1 = num / 10 Else go to Step 5 Step 4: Go to Step 3 Step 5: If (temp == sum) Then Print Armstrong Number Else Print Not an Armstrong Number EndIf Step 6: Stop |
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Example of Armstrong Number
153 = (1 * 1 * 1) + (5 * 5 * 5) + (3 * 3 * 3)
407 = (4 * 4 * 4) + (0 * 0 * 0) + (7 * 7 * 7)
371 = (3 * 3 * 3) + (7 * 7 * 7) + (1 * 1 * 1)
Armstrong Number Formula

Note: This Java program for Armstrong Number series is compiled on Linux Ubuntu 14.04 and written using gEdit editor. However, this Armstrong Number Java program is compatible with all other operating systems.
Method 1: Java Program To Check Armstrong Number using While Loop
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | import java.io.*; class Armstrong { public static void main(String args[]) throws Exception { int num, temp, sum = 0, rem = 0; BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); System.out.println("\nEnter an Integer:"); num = Integer.parseInt(br.readLine()); temp = num; while(num > 0) { rem = num%10; sum = sum + (rem * rem * rem); num = num/10; } if(temp == sum) { System.out.println("\n" + temp + " is an Armstrong Number\n"); } else { System.out.println("\n" + temp + " is Not an Armstrong Number\n"); } } } |
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Method 2: Simple Program For Armstrong Number in Java using While Loop
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | import java.io.*; class Armstrong { public static void main(String args[]) throws Exception { int num, temp, sum = 0, rem = 0; BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); System.out.println("\nEnter an Integer:"); num = Integer.parseInt(br.readLine()); temp = num; for(; num > 0; num = num / 10) { rem = num%10; sum = sum + (rem * rem * rem); } if(temp == sum) { System.out.println("\n" + temp + " is an Armstrong Number\n"); } else { System.out.println("\n" + temp + " is Not an Armstrong Number\n"); } } } |
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Output

Let’s discuss more on Armstrong number in Java programming in the comment section below if you have any compilation errors and any doubts about the same. For more information on Armstrong series, refer Wikipedia.