Understanding the Problem

To reverse a number, we need to rearrange its digits in the opposite order. For example, if the number is 12345, its reverse will be 54321.

Developing the Algorithm

To reverse a number, we can follow these steps:

1. Accept the number as input.
2. Convert the number to a string to access its individual digits.
3. Use string slicing to reverse the string.
4. Convert the reversed string back to an integer.
5. Return the reversed integer.

Writing the Python Code

def reverse_number(number):
    number_str = str(number)
    reversed_str = number_str[::-1]
    reversed_number = int(reversed_str)
    return reversed_number

# Test the function
number = 12345
reversed_number = reverse_number(number)
print("Original number:", number)
print("Reversed number:", reversed_number)

O/P

Original number: 12345
Reversed number: 54321

Time Complexity: O(N)

Code Explanation

We define a function reverse_number that takes the number as an argument and returns the reversed number.
We convert the number to a string using str() and store it in the variable number_str.
Using string slicing with [::-1], we reverse the string number_str and store it in reversed_str.
We convert reversed_str back to an integer using int() and assign it to reversed_number.
Finally, we return reversed_number.

Dry Run the Code

Let’s do a dry run of the code iteration-wise for number = 12345:

number_str is “12345”.
reversed_str is “54321”.
The loop ends, and we convert reversed_str back to an integer, resulting in reversed_number = 54321.

The code prints “Original number: 12345” and “Reversed number: 54321”.

In this tutorial, we have learned how to reverse a number in Python. By following the steps outlined, you can easily reverse any given number. The process involves converting the number to a string, using string slicing to reverse it, and converting it back to an integer.