Check Armstrong number in python

In this post, we learn how to write a python program to check for Armstrong numbers with a detailed explanation but before writing the program let’s understand what is Armstrong number.

What is Armstrong number?

Armstrong number is a number in which the sum of each digit powered to the total number of digits is same as the given number.

For example: 153

Another example: 1634

Armstrong number program in python

We are writing this program in three different ways

1. Simple by taking user input
2. By using function
3. using try-except block (Except the exception, if the user inputs wrong data)

Simple by taking user input

Questions may be asked like: Write a python program to check for Armstrong number by taking user input.

But before writing this program you should know about:

1. how to take user input in python
2. while-loop in python
3. if-else block in python

Source code

my_num = int(input('ENter a number: '))

power_of_my_num = len(str(my_num))

total = 0
i = my_num

while i > 0:
    remainder = i%10
    total += remainder**power_of_my_num
    i = i // 10


if total == my_num:
    print(f'{my_num} is Armstrong number')
else:
    print(f'{my_num} is not Armstrong number')

Output-1

ENter a number: 153
153 is Armstrong number

Output-2

ENter a number: 1635
1635 is not Armstrong number

By using function

Questions may be asked like: Write a python program to check for Armstrong number by using a user-defined function.

But before we jump into the program few things you should know about:

1. Function in python
2. while-loop
3. if-else block

Source code

def Armstrong_checker(num):
    power_of_num = len(str(num))

    sum = 0
    i = num

    while i>0:
        remainder = i%10
        sum += remainder**power_of_num
        i = i//10
    
    if sum == num:
        return True
    else:
        return False


my_number = int(input('ENter a number: '))

if Armstrong_checker(my_number):
    print(f'{my_number} is Armstrong number')
else:
    print(f'{my_number} is not Armstrong number')

Output-1:

ENter a number: 1634
1634 is Armstrong number

Output-2:

ENter a number: 145
145 is not Armstrong number

Using try-except block (Except the exception, if the user inputs wrong data)

Questions may be asked like: Write a python program to check for Armstrong number and except the exception, if the user inputs wrong data.

But before we jump into the program few things you should know about:

1. if-else
2. while-loop
3. function in python
4. try-except block in python

Source code

def Armstrong_checker(num):
    power_of_num = len(str(num))

    sum = 0
    i = num

    while i>0:
        remainder = i%10
        sum += remainder**power_of_num
        i = i//10
    
    if sum == num:
        return True
    else:
        return False



while True:
    try:
        my_number = int(input('ENter a number: '))
        break
    except Exception:
        print('only numbers are allowed pls enter again')


if Armstrong_checker(my_number):
    print(f'{my_number} is Armstrong number')
else:
    print(f'{my_number} is not Armstrong number')

Output-1:

ENter a number: one
only numbers are allowed pls enter again
ENter a number: 1
1 is Armstrong number

Output-2:

ENter a number: 1634
1634 is Armstrong number