Factorial Calculator - java

How can I make the program to perform a new or repeat the operation or ask the user to input again a number and know the factorial of it.
import java.util.Scanner;
public class Loops {
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
int num, num2 = 1, x, i;
System.out.println("-------------Factorial Calculator-------------");
System.out.print("Enter a positive integer: ");
num = input.nextInt();
if (num > 0) {
System.out.print(num + "! = ");
for (i = 1; i <= num; i++) {
if(i < num){
System.out.print(i + " x ");
num2 = num2 * i;
}
if(i == num){
System.out.print(i);
num2 = num2 * i;
System.out.println("\nThe factorial of " + num + " is " + num2);
System.out.println();
}
}
}else if (num < 0) {
System.out.println("Please input a valid integer. Program stopped.");
}
}
}


Put the code that computes the factorial in a separate method and call it from within a loop in main().
import java.util.Scanner;
public class Loops {
public static void printFactorial(int num) {
int i = 0;
int num2 = 0;
if (num > 0) {
System.out.print(num + "! = ");
for (i = 1; i <= num; i++) {
if(i < num){
System.out.print(i + " x ");
num2 = num2 * i;
}
if(i == num){
System.out.print(i);
num2 = num2 * i;
System.out.println("\nThe factorial of " + num + " is " + num2);
System.out.println();
}
}
}else if (num < 0) {
System.out.println("Please input a valid integer. Program stopped.");
System.exit(0);
}
}
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
int num = 0;
System.out.println("-------------Factorial Calculator-------------");
while ( true ) {
System.out.print("Enter a positive integer: ");
num = input.nextInt();
printFactorial(num);
}
}
}


Use a while loop
import java.util.Scanner;
public class Loops {
static boolean readInput = true;
public static void main(String[] args) {
while(readInput) calculateFactorial();
}
}
private static void calculateFactorial() {
Scanner input = new Scanner(System.in);
int num, num2 = 1, x, i;
System.out.println("-------------Factorial Calculator-------------");
System.out.print("Enter a positive integer: ");
num = input.nextInt();
if(num <= 0) {
readInput = false;
return;
}
if (num > 0) {
System.out.print(num + "! = ");
for (i = 1; i <= num; i++) {
if(i < num){
System.out.print(i + " x ");
num2 = num2 * i;
}
if(i == num){
System.out.print(i);
num2 = num2 * i;
System.out.println("\nThe factorial of " + num + " is " + num2);
System.out.println();
}
}
}else if (num < 0) {
System.out.println("Please input a valid integer. Program stopped.");
}
}


import java.util.Scanner;
public class Main {
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
boolean runMore = true;
while(runMore){
int num, num2 = 1, x, i;
System.out.println("-------------Factorial Calculator-------------");
System.out.print("Enter a positive integer: ");
num = input.nextInt();
if (num > 0) {
System.out.print(num + "! = ");
for (i = 1; i <= num; i++) {
if(i < num){
System.out.print(i + " x ");
num2 = num2 * i;
}
if(i == num){
System.out.print(i);
num2 = num2 * i;
System.out.println("\nThe factorial of " + num + " is " + num2);
System.out.println();
}
}
}else if (num < 0) {
System.out.println("Please input a valid integer. Program stopped.");
}
System.out.println("Want to contine : Enter '1' for yes and '0' for no");
int wantToContinue = input.nextInt();
if(wantToContinue==0){
runMore = false;
}
}
}
}


use while loop when user not typing a positif number :
System.out.print("Enter a positive integer: ");
num = input.nextInt();
while(num<0) {
System.out.println("Please input a valid integer. Program stopped.");
num = input.nextInt();
}
code :
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int num, num2 = 1, x, i;
System.out.println("-------------Factorial Calculator-------------");
System.out.print("Enter a positive integer: ");
num = input.nextInt();
input.nextLine();
while (num < 0) {
System.out.println("Please input a valid integer. Program stopped.");
System.out.print("Enter a positive integer: ");
num = input.nextInt();
}
if (num > 0) {
System.out.print(num + "! = ");
for (i = 1; i <= num; i++) {
if (i < num) {
System.out.print(i + " x ");
num2 = num2 * i;
}
if (i == num) {
System.out.print(i);
num2 = num2 * i;
System.out.println("\nThe factorial of " + num + " is " + num2);
System.out.println();
}
}
}
}
}


import java.util.Scanner;
public class FactorialCalculator1 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int num;
System.out.println("<------Factorial Calculator------>");
while ( true ) {
System.out.print("Enter a positive integer: ");
num = input.nextInt();
boolean runMore = true;
int i;
int num2 = 1;
if (num > 0) {
System.out.print(num + "! = ");
for (i = 1; i <= num; i++) {
if(i < num){
System.out.print(i + " x ");
num2 = num2 * i;
}
if(i == num){
System.out.print(i);
num2 = num2 * i;
System.out.println("\nThe factorial of " + num + " is: " + num2);
System.out.println();
}
}
}else if (num < 0) {
System.out.println("Invalid input! Program stopped!");
System.exit(0);
}
}
}
}

Related

How to find factorial and show result of counting in console?

public class Car {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int n = in.nextInt();
System.out.println(n+"!="+factorial(n));
}
public static int factorial(int num) {
return (num == 0) ? 1 : num * factorial (num - 1);
}
}
how make this code to text in console 3! = 1*2*3 = 6?

Don't use recursion for this. Besides, it isn't really efficient or necessary.
Scanner in = new Scanner(System.in);
int n = in.nextInt();
int fact = 1;
String s = n + "! = 1";
for (int i = 2; i <= n; i++) {
fact *= i;
s += "*" + i;
}
s += " = ";
System.out.println(s + fact);

There can be many ways to do it e.g. you can build the required string or print the trail while calculating the factorial. In the following example, I have done the former.
As an aside, you should check the input whether it is a positive integer.
import java.util.Scanner;
public class Car {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
System.out.print("Enter a positive integer: ");
int n = in.nextInt();
if (n >= 0) {
StringBuilder strFact = new StringBuilder();
int fact = factorial(n, strFact);
if (strFact.length() > 0) {
// Delete the last '*'
strFact.deleteCharAt(strFact.length() - 1);
System.out.println(n + "!= " + strFact + " = " + fact);
} else {
System.out.println(n + "!= " + fact);
}
} else {
System.out.println("This is an invalid input.");
}
}
public static int factorial(int num, StringBuilder strFact) {
int fact;
if (num == 0) {
fact = 1;
} else {
fact = num * factorial(num - 1, strFact);
strFact.append(num + "*");
}
return fact;
}
}
A sample run:
Enter an integer: 3
3!= 1*2*3 = 6

Finding the smallest, largest, and middle values in Java

I did with this code. Is it correct way? I want to sort the numbers in ascending order. Is there better way for this?
import java.lang.Math;
public class Numbers
{
public static void main(String[] args)
{
int a=1;
int b=2;
int c=3;
if (a<b && a<c)
System.out.println("Smallest: a");
else if (a>b && a>c)
System.out.println("Biggest: a");
else if (a>b && a<c)
System.out.println("Mid: a");
else if (a<b && a>c)
System.out.println("Mid: a");
if (b<c && b<a)
System.out.println("Smallest: b");
else if (b>c && b>a)
System.out.println("Biggest: b");
else if (b>c && b<a)
System.out.println("Mid: b");
else if (b<c && b>a)
System.out.println("Mid: b");
if (c<a && c<b)
System.out.println("Smallest: c");
else if (c>a && c>b)
System.out.println("Biggest: c");
else if (c>a && c<b)
System.out.println("Mid: c");
else if (c<a && c>b)
System.out.println("Mid: c");
}
}

Expanding on Steve's answer (I assume you are new to Java and need a more complete example):
import java.util.Arrays;
public class Numbers
{
public static void main(String[] args)
{
int a=3;
int b=2;
int c=1;
int[] numbers = {a,b,c};
Arrays.sort(numbers);
System.out.println("The highest number is "+numbers[2]);
System.out.println("The middle number is "+numbers[1]);
System.out.println("The lowest number is "+numbers[0]);
}
}

You can store the three numbers in an array and then do
Arrays.sort(numbers);
/* numbers[0] will contain your minimum
* numbers[1] will contain the middle value
* numbers[2] will contain your maximum
*/
That's all!

In general it would be best to use a loop and a array for this type of thing that way if you have more than 3 numbers it will still work. Also you wont have to type nearly as much. Try something like this for finding the smallest number.
MyArray = new int[3];
MyArray[0] = 1;
MyArray[1] = 2;
MyArray[2] = 3;
int temp = a;
for (int i = 0; i < (number of numbers to check in this case 3); i++){
if (MyArray[i] < temp){
temp = MyArray[i];
}
}
System.out.println("Smallest number is: " + temp);

import java.util.Scanner;
public class SortingIntegers {
public static void main (String[] args){
int num1;
int num2;
int num3;
int largerstNum;
int smallestNum;
int middleNum;
Scanner sc = new Scanner(System.in);
System.out.println("Please enter the First Integer");
num1 = sc.nextInt();
System.out.println("Pleas enter the Second Integer");
num2 = sc.nextInt();
System.out.println("Please enter the third Integer");
num3 = sc.nextInt();
if (num1 > num2){
if (num1 > num3){
largerstNum = num1;
if (num2 > num3){
middleNum = num2;
smallestNum = num3;
}else {
middleNum = num3;
smallestNum = num2;
}
}
}else {
if (num1 > num3){
middleNum = num1;
if (num2 > num3){
largerstNum = num2;
smallestNum = num3;
}else {
largerstNum = num3;
smallestNum = num2;
}
}else {
smallestNum =num1;
if (num2 > num3){
largerstNum = num2;
middleNum = num3;
}else {
largerstNum = num3;
middleNum = num2;
}
}
System.out.println("Highest Number is : " + largerstNum);
System.out.println("Smallest Number is : " + smallestNum);
System.out.println("Middle Number is : " + middleNum);
}
}
}

How to modify this code to print the 3 integers in order?

I have a code that prints the biggest integer between 3 integers and I want to sort these 3 integers (like num < num1 < num2).
I want to modify my code to achieve this, how can I do it?
import java.util.Scanner;
public class digits {
public static void main(String[] args) {
int num = 0;
int num1 = 0;
int num2 = 0;
int big = 0;
System.out.println("Please insert 3 numbers: ");
Scanner number = new Scanner(System.in);
if (number.hasNextInt()) {
num = number.nextInt();
big = num;
}
if (number.hasNextInt()) {
num1 = number.nextInt();
if (num1 > num) {
big = num1;
}
}
if (number.hasNextInt()) {
num2 = number.nextInt();
if (num2 > num && num2 > num1) {
big = num2;
}
System.out.println(big + ">" + num1 + ">" + num);
} else {
System.out.println("Error: Invalid Value.");
}
}
}

Try below code
public static void main(String[] args) {
System.out.println("Please insert 3 numbers: ");
Scanner number = new Scanner(System.in);
Integer[] input = new Integer[3];
int i = 0;
while (i != 3) {
input[i++] = number.nextInt();
}
number.close();
Arrays.sort(input, Collections.reverseOrder());
StringBuffer sb = new StringBuffer();
for (Integer a : input) {
sb.append(a).append(">");
}
System.out.println(sb.substring(0, sb.length() - 1));
}

if(num1>num)
{
big=num1;
}
Change this to:
if(num1>num)
{
big=num1;
}
else
{
// swap num1 and num
int tmp = num;
num = num1;
num1 = num;
}
Also change
if(num2>num && num2>num1)
{
big=num2;
}
to
if(num2>num1)
{
big=num2;
}
else
{
// num1 is largest, so swap num1 and num2
int tmp = num1;
num1 = num2;
num2 = tmp;
if(num > num1){
//swap num and num1
int t = num1;
num1 = num;
num = t;
}
}

Look at your code: you're choosing the biggest of the three numbers (big), but you never change num1 or num.
So, your result will always be: greater number>second value from System.in>third value from System.in.
In other words, you're sorting only the higher value.

Something like this should work
import java.util.Scanner;
public class digits {
public static void main(String[] args)
{
int[] nums = new int[3];
int k = 0;
System.out.println("Please insert 3 numbers: ");
Scanner number = new Scanner (System.in);
while (number.hasNext() && k < 3) {
int i = 0;
try {
i = Integer.parseInt(number.nextLine());
}
catch (NumberFormatException e) {
System.out.println("Error: Invalid Value.");
}
nums[k] = i;
k++;
}
Arrays.sort(nums);
System.out.println(nums[2]+ ">" +nums[1]+ ">" +nums[0]);
}
}

How can I get this program to print out the numbers the user entered?

Here's my code:
import java.util.*;
public class InputSum
{
public static void main(String[]args)
{
Scanner input = new Scanner(System.in);
System.out.print("Please enter integer values (-1 to to display numbers & sum): ");
int i = input.nextInt();
int j = 0;
while (i != -1)
{
j += i;
i = input.nextInt();
}
System.out.println("Entered Number: " + i);
System.out.println("The Sum: " + j);
}
}
As of now my output is:
Entered Number: -1
The Sum: (Sum of the numbers entered)

Print them inside the loop :
while (i != -1)
{
System.out.println("Entered Number: " + i);
j += i;
i = input.nextInt();
}
System.out.println("The Sum: " + j);
Or it you want to print them in a single line :
List numbers = new ArrayList<Integer>();
while (i != -1)
{
numbers.add(i);
j += i;
i = input.nextInt();
}
System.out.println("Entered Numbers: " + numbers);
System.out.println("\nThe Sum: " + j);

public static void main(String[] args) {
Scanner input = new Scanner(System.in);
ArrayList<Integer> numbers = new ArrayList<Integer>();
System.out
.print("Please enter integer values (-1 to to display numbers & sum): ");
int i = input.nextInt();
int j = 0;
while (i != -1) {
numbers.add(i);
j += i;
i = input.nextInt();
}
System.out.println("Entered Numbers: ");
for (int a = 0; a < numbers.size(); a++) {
System.out.print(" " + numbers.get(a));
}
System.out.println("The Sum: " + j);
}
This should work to print the numbers. You can use an arraylist to store the numbers and then if you need them for later calculations they are still stored in the arraylist.

package net.rajkannan.stackoverflow;
import java.util.*;
public class InputSum {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out
.print("Please enter integer values (-1 to to display numbers & sum): ");
int i = input.nextInt();
int j = 0;
String numbers = "";
while (i != -1) {
j += i;
numbers = numbers + i + " ";
i = input.nextInt();
}
System.out.println("Entered Numbers: " + numbers);
System.out.println("The Sum: " + j);
}
}

To check if a number is Armstrong number using java

this is my program:
public class ArmstrongNumber {
public static void main(String args[]) {
int n = 0, temp = 0, r = 0, s = 0;
Scanner in = new Scanner(System.in);
System.out.println("Enter a number ");
if (in.hasNextInt()) {
n = in.nextInt(); // if there is another number
} else {
n = 0;
}
temp = n;
while (n != 0) {
r = n % 10;
s = s + (r * r * r);
n = n / 10;
}
if (temp == s) {
System.out.println(n + " is an Armstrong Number");
} else {
System.out.println(n + " is not an Armstrong Number");
}
}
}
output:
Exception in thread "main" java.lang.NoClassDefFoundError
I tried it using DataInputStream but still getting same error.

// To check the given no is Armstrong number (Java Code)
class CheckArmStrong{
public static void main(String str[]){
int n=153,a, b=0, c=n;
while(n>0){
a=n%10; n=n/10; b=b+(a*a*a);
System.out.println(a+" "+n+" "+b); // to see the logic
}
if(c==b) System.out.println("Armstrong number");
else System.out.println(" Not Armstrong number");
}
}

Find any digit is Armstrong number or not using loop
for(int arm_num = 0 ; arm_num < 100000 ; arm_num++)
{
String[] data = String.valueOf(arm_num).split("(?<=.)");
int lngth = String.valueOf(arm_num).length();
int arm_t_num = 0;
int ary[] = new int[lngth];
for(int i = 0 ; i < lngth ; i++)
{
ary[i] = Integer.parseInt(data[i]);
for(int x = 0 ; x < lngth-1 ; x++)
{
ary[i] = ary[i] * Integer.parseInt(data[i]);
}
arm_t_num+=ary[i];
}
if(arm_num == arm_t_num)
{
System.out.println("Number is ArmStrong : "+arm_num);
}
}

you need to set CLASS_PATH variable and point it to where ever your class file is
then this should work
I have tried it locally, refer my answer to check how to set class path and how to compile and run java code using command prompt

//This is my program to check whether the number is armstrong or not!!
package myprogram2;
public class Myprogram2 {
public static void main(String[] args)
{
String No="407";
int length_no=No.length();
char[] S=new char[length_no];
int[] b = new int[length_no];
int arm=0;
for(int i=0;i<length_no;i++)
{
S[i]=No.charAt(i);
b[i]=Character.getNumericValue(S[i]);
//System.out.print(b[i]);
arm=arm + (b[i]*b[i]*b[i]);
System.out.println(arm);
}
//System.out.println(" is the number \n now Checking for its Armstrong condition");
int orgno = Integer.parseInt(No);
if (orgno==arm)
System.out.println("YESm its an armstrong");
else
System.out.println("\n<<Not an armstrong>>");
//System.out.println(length_no);
System.out.println("Original number is "+orgno);
System.out.println("Sum of cubes "+arm);
}
}

There are a couple of nice String-based solutions and numeric solutions with single-letter variable names.
Consider this to make sense of how it works numerically, which includes a couple of interesting numeric tricks:
import java.io.*;
public class Armstrong
{
public static void main(String args[]) throws IOException
{
InputStreamReader read = new InputStreamReader(System.in);
BufferedReader in = new BufferedReader(read);
int modifiedNumber, originalNumber, modifiedNumberWithUnitsDigitZero,
unitsDigit, runningSum;
System.out.println("Enter your number:");
modifiedNumber = Integer.parseInt(in.readLine());
runningSum = 0;
originalNumber = modifiedNumber;
while(modifiedNumber > 0)
{
modifiedNumberWithUnitsDigitZero = modifiedNumber / 10 * 10;
unitsDigit = modifiedNumber - modifiedNumberWithUnitsDigitZero;
runningSum += unitsDigit * unitsDigit * unitsDigit;
modifiedNumber = modifiedNumber / 10;
}
System.out.println("The number " + originalNumber
+ (originalNumber == runningSum ? " IS" : " is NOT")
+ " an Armstrong number because sum of cubes of digits is " + runningSum);
}
}

import java.util.Scanner;
public class Amst {
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
System.out.println("Enter The No. To Find ArmStrong Check");
int i = sc.nextInt();
int sum = 0;
for(int j = i; j>0 ; j = j/10){
sum = sum + ((j%10)*(j%10)*(j%10));
}
if(sum == i)
System.out.println("Armstrong");
else
System.out.println("Not Armstrong");
}
}

For 'N' digit amstrong number
package jjtest;
public class Amstrong {
public static void main(String[] args) {
// TODO Auto-generated method stub
int num=54748;
int c=0;
int temp=num;
int b=1;
int length = (int)(Math.log10(num)+1);
while(num>0){
int r = num%10;
num=num/10;
int a =1;
for(int i=1;i<=length;++i){
b=b*r;
}
c = c + b;
b=1;
}
System.out.println(c);
if(c==temp){
System.out.println("its an amstrong number");
}else{
System.out.println("its not an amstrong number");
}
}
}

This is the simple logic for Armstrong number program :
for (int i = number; i > 0; i = i / 10)
{
remainder = i % 10;
sum = sum + remainder * remainder * remainder;
}
if(sum == number)
{
System.out.println("\n" + number + " is an Armstrong Number\n");
}
Reference :
http://topjavatutorial.com/java/java-programs/java-program-to-check-if-a-number-is-armstrong-number/

import java.util.Scanner;
/* a number is armstrong if the sum of cubes if individual digits of
a number is equal to the number itself.for example, 371 is
an armstrong number. 3^3+7^3+1^3=371.
some others are 153,370,407 etc.*/
public class ArmstrongNumber {
public static void main(String args[]) {
int input, store, output=0, modolus;
Scanner in = new Scanner(System.in);
System.out.println("Please enter a number for ckecking.");
input = in.nextInt();
store = input;
while(input != 0) {
modolus = input % 10;
output = output + (modolus * modolus * modolus);
input = input / 10;
}
System.out.println(output);
if(store == output) {
System.out.println("This is an armstrong number.");
} else {
System.out.println("This is not an armstrong number.");
}
in.close();
}
}

import java.util.*;
public class ArmstrongNumber
{
public static void main( String[] args )
{
int n = 0, temp = 0, r = 0, s = 0;
Scanner in = new Scanner(System.in);
System.out.println("Enter a number ");
if (in.hasNextInt()) {
n = in.nextInt(); // if there is another number
} else {
n = 0;
}
temp = n;
while (n != 0) {
r = n % 10;
s = s + (r * r * r);
n = n / 10;
}
if (temp == s) {
System.out.println(temp + " is an Armstrong Number");
} else {
System.out.println(temp + " is not an Armstrong Number");
}
}
}
You missed to import java.util package
Change n to temp in S.O.P

import java.util.Scanner;
public class AmstrongNumber {
public static void main(String[] args) {
System.out.println("Enter the number");
Scanner scan=new Scanner(System.in);
int x=scan.nextInt();
int temp2=0;
String s1 = Integer.toString(x);
int[] a = new int[s1.length()];
int[] a1 = new int[s1.length()];
for (int i = 0; i < s1.length(); i++){
a[i] = s1.charAt(i)- '0';
int temp1=a[i];
a1[i]=temp1*temp1*temp1;
}
for (int i = 0; i < s1.length(); i++){
temp2=temp2+a1[i];
if(i==s1.length()-1){
if(x==temp2){
System.out.println("Amstrong num");
}else{
System.out.println("Not !");
}
}
}
}
}

private static boolean isArmstrong(int num) {
int totalSum = 0;
int copyNum = num;
while (num != 0) {
int reminder = num % 10;
int cubeOfReminder = reminder * reminder * reminder;
totalSum = totalSum + cubeOfReminder;
num = num / 10;
}
if (copyNum == totalSum)
return true;
return false;
}

public class Testamstrong
{
public static void main(String...strings) {
int num = 153,temp;
temp = num;
if(temp == amstrongNumber(num)) {
System.out.println("Number is amstrong number...");
}
else {
System.out.println("Number is not amstrong number...");
}
}
public static int amstrongNumber(int num) {
int count=0,sum=0;
count = String.valueOf(num).length();
char[] ch = String.valueOf(num).toCharArray();
for(char ch1:ch) {
int num1 = Character.getNumericValue(ch1);
sum += Math.pow(num1, count);
}
return sum;
}
}

Find Armstrong number using for loops (with example)
import java.util.*;
public class ArmstorngNumber {
public static void main(String args[]) {
int cube, num, quo, n;
int s = 0;
do
{
System.out.println("Enter Your Number");
Scanner sc = new Scanner(System.in);
num = sc.nextInt();//153
n = num;
for (int i = 0; i < 10; i++) {
int rem = num % 10;//3
quo = num / 10; //15
cube = rem * rem * rem;//9
s = s + cube;//0+9
num = quo;//0
}
System.out.println(s);
System.out.println(n);
if (s == n) {
System.out.println("The number is Armstrong");
System.out.println("-------------------------------------");
}
else {
System.out.println("The number is not Armstrong");
System.out.println("-------------------------------------");
}
}
while (n > 0);
}
}

Check the Armstrong number of any number [java] [Armstrong]
import java.util.*;
public class Armstrong {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("enter any number?");
int x = sc.nextInt();
int n=0;
int number = x;
int j =x;
int result = 0 ,remainder;
while (x!=0) {
x/=10;
++n;
}
for(;j>0 ;j=j/10) {
remainder=j%10;
result+=Math.pow(remainder, n);
}
if (number==result) {
System.out.print(number +" is Armstrong ");
}
else
System.out.print(number +" is not Armstrong");
}
}

here is my code, please check if this works for you!
import java.util.Scanner;
public class Armstromg {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Please enter the number: ");
int num = sc.nextInt();
int length = 0;
int temp1 = num;
while(temp1 != 0) {
temp1/=10;
length+=1;
}
int result = 1;
int temp2 = num;
for(int i = 1; i <= length; i++) {
temp2 = temp2 % 10;
result*=Math.pow(temp2,length);
}
if(result == num) {
System.out.print("The number is an armstrong number!");
} else {
System.out.print("The number is not an armstrong number");
}
}
}

package Loops;
public class ArmStrongNumber {
public static void main(String[] args) {
int digit1, digit2, digit3;
int number = 153;
int temp = number;
digit1 = number % 10;
number = number / 10;
digit2 = number % 10;
number = number / 10;
digit3 = number % 10;
if ((digit1 * digit1 * digit1) + (digit2 * digit2 * digit2) + (digit3 * digit3 * digit3) == temp) {
System.out.println(+temp + " Number is Armstrong ");
} else {
System.out.println("Number is not Armstrong");
}
}
}

//Not limited to 3 digit integers
public static void main(String[] args)
{
int num = 54748,a,sum=0;
int x = num;
int p =Integer.toString(num).length();
while (num !=0)
{
a = num%10;
num = num/10;
sum = sum + (int) Math.pow(a, p);
}
if (x==sum)
System.out.println("Its an Armstrong number");
else
System.out.println("Not an Armstrong number");
}
}

Scanner input = new Scanner (System.in);
int num , counter = 0 ,temp;
System.out.print("Enter Nmber :");
num = input.nextInt();
int lnum = num;
while ( num != 0 ){
num = num/10 ;
counter++;
}
int store_num_keyboard_input = lnum;
int new_tot = 0;
int c = counter;
while(lnum > 0){
temp = lnum % 10;
lnum = lnum / 10 ;
int m = 0; //m is counter
int tot = 1;
while (m != c){
tot = tot * temp;
m++;
}
new_tot = new_tot + tot;
}
System.out.println("new total "+ new_tot );
if(new_tot == store_num_keyboard_input){
System.out.println(store_num_keyboard_input + " is an Armstrong number" );
}
else{
System.out.println(store_num_keyboard_input + " is not an Armstrong number" );
}

My answer using JAVA 8
tested for..[1, 153, 370, 371, 407]
public class Armstrong {
public static boolean isArmstrong(int num) {
return num == getArmstrongSum(num);
}
public static int getArmstrongSum(int num) {
int pow = String.valueOf(num).length();
return IntStream.iterate(num, i -> i / 10)
.limit(pow)
.map(i -> (int) Math.pow(i % 10, 3))
.sum();
}
public static void main(String[] args) {
System.out.println(isArmstrong(153));
}
}
Thank you.

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