How to Write Python Program For Armstrong Number Using While Loop, For Loop, Functions, and Recursion?. We also show you, Python program to print Armstrong Numbers between 1 to n.

## Python Armstrong Number

If the given number is equal to the sum of the Nth power of each digit present in that integer, then that number can be an Armstrong Number in Python. For example, 370 is Armstrong Number.

Number of individual digits in 370 = 3

370 = 3³ + 7³ + 0³

= 27 + 343 + 0 = 370

The below steps show you the common approach to check for the Armstrong Number in Python

**Python Armstrong Number Steps:**

- The user has to enter any number.
- Count the Number of individual digits (For Example, 370 means 3).
- Divide the given number into individual digits (For Example, Divide 370 into 3, 7, and 0).
- Calculate the power of n for each individual and add those numbers.
- Compare the original value with Sum value.
- If they exactly matched, then it is an Armstrong number else it is not Armstrong.

## Python Program for Armstrong Number Using While Loop

This Python program allows the user to enter any positive integer. And then, this Python program checks whether a number is Armstrong Number or Not using the While Loop

# Python Program For Armstrong Number using While Loop Number = int(input("\nPlease Enter the Number to Check for Armstrong: ")) # Initializing Sum and Number of Digits Sum = 0 Times = 0 # Calculating Number of individual digits Temp = Number while Temp > 0: Times = Times + 1 Temp = Temp // 10 # Finding Armstrong Number Temp = Number while Temp > 0: Reminder = Temp % 10 Sum = Sum + (Reminder ** Times) Temp //= 10 if Number == Sum: print("\n %d is Armstrong Number.\n" %Number) else: print("\n %d is Not a Armstrong Number.\n" %Number)

**OUTPUT**

**ANALYSIS**

This Python Armstrong number program allows the user to enter any positive integer and then, that number assigned to variable Number.

Next, We assign the original value to the Temp variable. It helps to preserve our original value and then do all the manipulation on the Temp variable.

Below While loop makes sure that the given number is greater than 0, statements inside the while loop split the numbers and count number of individual digits inside the given number. If you don’t understand the logic, Please refer Python Program to find Number Of Digits in a Number article.

while Temp > 0: Times = Times + 1 Temp = Temp // 10

The Python Second While loop makes sure that the given number is greater than 0. Let us see the working principle of this while loop in iteration wise

while Temp > 0: Reminder = Temp % 10 Sum = Sum + (Reminder ** Times) Temp //= 10

User Entered value for this Python Program For Armstrong Number : Number = 9474 and Sum = 0

Temp = Number

Temp = 9474

**First Iteration**

Reminder = Temp %10

Reminder = 9474 % 10 = 4

Sum = Sum + pow (Reminder, Times)

For this example, Times =4 because number of digits in 9474 = 4. So,

Sum = Sum + (Reminder * Reminder * Reminder * Reminder)

Sum = 0 + (4 * 4 * 4 * 4)

Sum = 0 + 256

Sum = 256

Temp = Temp /10

Temp = 9474 /10

Temp = 947

**NOTE:** If the number of digits count is 5, then Reminder multiplied by 5 times.

**Second Iteration**

From the Python Program For Armstrong Number first Iteration, the values of both Temp and Sum changed as Temp = 163 and Sum = 256

Reminder = Temp %10

Reminder = 947 % 10 = 7

Sum = 256 + (7 * 7 * 7 * 7)

Sum = 256 + 2401

Sum = 2657

Temp = Temp /10

Temp = 163 /10

Temp = 94

**Third Iteration**

From the Third Iteration, the values of Temp = 94 and Sum = 2657.

Reminder = Temp %10

Reminder = 94 % 10 = 4

Sum = 2657 + (4 * 4 * 4 * 4)

Sum = 2657 + 256

Sum = 2913

Temp = Temp /10

Temp = 94 /10

Temp = 9

**Python Program For Armstrong Number Fourth Iteration**

From the Fourth Iteration, the values of Temp = 9 and Sum = 2913

Reminder = Temp %10

Reminder = 9 % 10 = 0

Sum = Sum + (Reminder * Reminder * Reminder * Reminder)

Sum = 2913 + (9 * 9 * 9 * 9)

Sum = 2913 + 6561

Sum = 9474

Temp = Temp /10

Temp = 9/10

Temp = 0

**Here **Number = 0, so the while loop condition fails.

if ( Number == Sum ) – Condition check whether the user enter number is exactly equal to Sum number or not. If this condition is True, then it is Armstrong else the given number is not Armstrong number.

Let me check if ( Number == Sum )

if(9474 == 9474) –TRUE, Means Armstrong

**NOTE: **If you are finding the Python Armstrong number below 1000, remove the while loop to count the number of digits in a number, and then replace the below code

Sum = Sum + (Reminder ** Times); With Sum = Sum + (Reminder * Reminder * Reminder)

## Python Program for Armstrong Number Using For Loop

This Python program allows the user to enter any positive integer and then, this program checks whether a number is Armstrong Number or Not using Python For Loop

# Python Program For Armstrong Number using For Loop Number = int(input("\nPlease Enter the Number to Check for Armstrong: ")) # Initializing Sum and Number of Digits Sum = 0 Times = 0 # Calculating Number of individual digits Temp = Number while Temp > 0: Times = Times + 1 Temp = Temp // 10 # Finding Armstrong Number Temp = Number for n in range(1, Temp + 1): Reminder = Temp % 10 Sum = Sum + (Reminder ** Times) Temp //= 10 if Number == Sum: print("\n %d is Armstrong Number.\n" %Number) else: print("\n %d is Not a Armstrong Number.\n" %Number)

**OUTPUT**

We just replaced the While loop in the above Python Armstrong number example with the For loop. If you don’t understand the for loop, then please refer For Loop article here: Python For Loop

## Python Program for Armstrong Number Using Functions

This Python program allows the user to enter any positive integer. Then, this program checks whether a number is Armstrong Number or Not using Functions

# Python Program For Armstrong Number using Functions def Armstrong_Number(Number): # Initializing Sum and Number of Digits Sum = 0 Times = 0 # Calculating Number of individual digits Temp = Number while Temp > 0: Times = Times + 1 Temp = Temp // 10 # Finding Armstrong Number Temp = Number for n in range(1, Temp + 1): Reminder = Temp % 10 Sum = Sum + (Reminder ** Times) Temp //= 10 return Sum #End of Function #User Input Number = int(input("\nPlease Enter the Number to Check for Armstrong: ")) if (Number == Armstrong_Number(Number)): print("\n %d is Armstrong Number.\n" %Number) else: print("\n %d is Not a Armstrong Number.\n" %Number)

**OUTPUT**

**ANALYSIS**

In this Python Program For Armstrong Number example, we defined the following function to perform all the necessary calculations and return Sum.

def Armstrong_Number(Number):

When the compiler reaches the following code inside the If statement then, the compiler immediately jumps to the above-specified function.

Armstrong_Number(Number)

We already explained the LOGIC above example.

## Python Program for Armstrong Number Using Recursion

This program allows us to enter any positive integer. Next, this Python program checks whether a number is Armstrong Number or Not using Recursion concept.

# Python Program For Armstrong Number using Recursion # Initializing Number of Digits Sum = 0 Times = 0 # Calculating Number of individual digits def Count_Of_Digits(Number): global Times if(Number > 0): Times = Times + 1 Count_Of_Digits(Number // 10) return Times #End of Count Of Digits Function # Finding Armstrong Number def Armstrong_Number(Number, Times): global Sum if(Number > 0): Reminder = Number % 10 Sum = Sum + (Reminder ** Times) Armstrong_Number(Number //10, Times) return Sum #End of Armstrong Function #User Input Number = int(input("\nPlease Enter the Number to Check for Armstrong: ")) Times = Count_Of_Digits(Number) Sum = Armstrong_Number(Number, Times) if (Number == Sum): print("\n %d is Armstrong Number.\n" %Number) else: print("\n %d is Not a Armstrong Number.\n" %Number)

**OUTPUT**

**ANALYSIS**

In this Python Program for Armstrong Number example, we defined two recursive functions. The following function accept integer values as parameter value and count the number of individual digits in a number recursively.

def Count_Of_Digits(Number):

The following function accepts two integer values as parameter values. And it performs all the necessary calculations and return Sum.

def Armstrong_Number(Number, Times):

The following Statement help to call the function Recursively with updated value. If you miss this statement, then after completing the first line it will terminate. For example,

Armstrong_Number(Number //10, Times)

Number = 153

Then the output = 27

Let’s see the If statement inside the above-specified functions

if (Number > 0) check whether the number is greater than 0 or not. For Recursive functions, it is essential to place a condition before using the function recursively. Otherwise, we end up in infinite execution (Same like infinite Loop).

Please be careful :)

## Python Program to Find Armstrong Numbers between the 1 to n

This program allows you to enter minimum and maximum values. This Python program returns Armstrong Numbers between the Minimum and Maximum values.

# Python Program to Find Armstrong Numbers between the 1 to n Minimum = int(input("Please Enter the Minimum Value: ")) Maximum = int(input("\n Please Enter the Maximum Value: ")) for Number in range(Minimum, Maximum + 1): # Initializing Sum and Number of Digits Sum = 0 Times = 0 # Calculating Number of individual digits Temp = Number while Temp > 0: Times = Times + 1 Temp = Temp // 10 # Finding Armstrong Number Temp = Number while Temp > 0: Reminder = Temp % 10 Sum = Sum + (Reminder ** Times) Temp //= 10 if Number == Sum: print(Number)

**OUTPUT**

**ANALYSIS:**

The following statements present in this Python Armstrong number program allows the user to enter minimum and maximum values.

Minimum = int(input("Please Enter the Minimum Value: ")) Maximum = int(input("\n Please Enter the Maximum Value: "))

The Python for Loop helps to iterate between Minimum and Maximum Variables. Iteration starts at the Minimum, and then it won’t exceed the Maximum variable.

for Number in range(Minimum, Maximum + 1):

if(Number == Sum) -– condition check whether the sum of the power N for each digit present in that integer is equal to a given number or not. When the condition is True, it is an Armstrong else the given number is not Armstrong number in Python.

If this condition is True, the below statement printed.

print(Number)