In the previous article, we have discussed Python Program to Print Multiplication Table using Recursion

Given a number and the task is to check whether the given number is an Armstrong number or not using recursion.

**Recursion:**

Recursion is the process by which a function calls itself directly or indirectly, and the associated function is known as a recursive function. Certain issues can be addressed fairly easily using a recursive approach. Towers of Hanoi (TOH), Inorder /Preorder/Postorder Tree Traversals, DFS of Graph, and other analogous issues are examples.

**Examples:**

**Example1:**

**Input:**

Given Number = 153

**Output:**

The above given Number is an Armstrong Number.

**Example2:**

**Input:**

Given Number = 100

**Output:**

The above given Number is Not an Armstrong Number.

## Program to Check Armstrong Number using Recursion in Python

Below are the ways to check whether the given number is an Armstrong number or not using recursion:

### Method #1: Using Recursion (Static Input)

**Approach:**

- Give the number as static input and store it in a variable.
- Take a variable say
**rslt_sum**and initialize its value to 0. - Pass the given number as an argument to the
**chek_ArmstrngNumb**function. - Create a recursive function to say
**chek_ArmstrngNumb**which takes the given number as an argument and returns the**rslt_sum.** - Make the
**rslt_sum**a global declaration. - Check if the given number is not equal to 0 using the if conditional statement.
- If the statement is true, get the last digit of the given number using the modulus operator and store it in another variable
**k**. - Calculate the value of k raised to power 3 using the pow() function and add it to the
**rslt_sum.** - Store it in the same variable
**rslt_sum.** - Pass the given number divided by 10 as an argument to the
**chek_ArmstrngNumb**function(which removes the last digit of the number) {Recursive Logic}. - Return
**rslt_sum.** - Check if the
**chek_ArmstrngNumb**which takes the given number as an argument is equal to the given number using the if conditional statement. - If the statement is true, then print “The above-given number is an Armstrong Number”.
- Else print “The above-given number is not an Armstrong Number”.
- The Exit of the Program.

**Below is the implementation:**

# Create a recursive function to say chek_ArmstrngNumb which takes the given number as # an argument and returns the rslt_sum. def chek_ArmstrngNumb(gven_numb): # Make the rslt_sum a global declaration. global rslt_sum # Check if the given number is not equal to 0 using the if conditional statement. if (gven_numb != 0): # If the statement is true, get the last digit of the given number using the modulus # operator and store it in another variable k. k = gven_numb % 10 # Calculate the value of k raised to power 3 using the pow() function and add it to the # rslt_sum. # Store it in the same variable rslt_sum. rslt_sum += pow(k, 3) # Pass the given number divided by 10 as an argument to the chek_ArmstrngNumb function # (which removes the last digit of the number) {Recursive Logic}. chek_ArmstrngNumb(gven_numb//10) # Return rslt_sum. return rslt_sum # Give the number as static input and store it in a variable. gven_numb = 153 # Take a variable say rslt_sum and initialize its value to 0. # Pass the given number as an argument to the chek_ArmstrngNumb function. rslt_sum = 0 # Check if the chek_ArmstrngNumb which takes the given number as an argument is equal # to the given number using the if conditional statement. if (chek_ArmstrngNumb(gven_numb) == gven_numb): # If the statement is true, then print "The above given number is an Armstrong Number". print("The above given Number is an Armstrong Number.") else: # Else print "The above given number is not an Armstrong Number". print("The above given Number is Not an Armstrong Number.")

**Output:**

The above given Number is an Armstrong Number.

### Method #2: Using Recursion (User Input)

**Approach:**

- Give the number as user input using the int(input()) function and store it in a variable.
- Take a variable say
**rslt_sum**and initialize its value to 0. - Pass the given number as an argument to the
**chek_ArmstrngNumb**function. - Create a recursive function to say
**chek_ArmstrngNumb**which takes the given number as an argument and returns the**rslt_sum.** - Make the
**rslt_sum**a global declaration. - Check if the given number is not equal to 0 using the if conditional statement.
- If the statement is true, get the last digit of the given number using the modulus operator and store it in another variable
**k**. - Calculate the value of k raised to power 3 using the pow() function and add it to the
**rslt_sum.** - Store it in the same variable
**rslt_sum.** - Pass the given number divided by 10 as an argument to the
**chek_ArmstrngNumb**function(which removes the last digit of the number) {Recursive Logic}. - Return
**rslt_sum.** - Check if the
**chek_ArmstrngNumb**which takes the given number as an argument is equal to the given number using the if conditional statement. - If the statement is true, then print “The above-given number is an Armstrong Number”.
- Else print “The above-given number is not an Armstrong Number”.
- The Exit of the Program.

**Below is the implementation:**

# Create a recursive function to say chek_ArmstrngNumb which takes the given number as # an argument and returns the rslt_sum. def chek_ArmstrngNumb(gven_numb): # Make the rslt_sum a global declaration. global rslt_sum # Check if the given number is not equal to 0 using the if conditional statement. if (gven_numb != 0): # If the statement is true, get the last digit of the given number using the modulus # operator and store it in another variable k. k = gven_numb % 10 # Calculate the value of k raised to power 3 using the pow() function and add it to the # rslt_sum. # Store it in the same variable rslt_sum. rslt_sum += pow(k, 3) # Pass the given number divided by 10 as an argument to the chek_ArmstrngNumb function # (which removes the last digit of the number) {Recursive Logic}. chek_ArmstrngNumb(gven_numb//10) # Return rslt_sum. return rslt_sum # Give the number as user input using the int(input()) function and # store it in a variable. gven_numb = int(input("Enter some random number = ")) # Take a variable say rslt_sum and initialize its value to 0. # Pass the given number as an argument to the chek_ArmstrngNumb function. rslt_sum = 0 # Check if the chek_ArmstrngNumb which takes the given number as an argument is equal # to the given number using the if conditional statement. if (chek_ArmstrngNumb(gven_numb) == gven_numb): # If the statement is true, then print "The above given number is an Armstrong Number". print("The above given Number is an Armstrong Number.") else: # Else print "The above given number is not an Armstrong Number". print("The above given Number is Not an Armstrong Number.")

**Output:**

Enter some random number = 100 The above given Number is Not an Armstrong Number.

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