# python tutorial - Python Program to Reverse a Number - learn python - python programming

## Python Program to Reverse a Number Using While Loop

• This program allows the user to enter any positive integer and then, this program will reverse a number using Python While Loop Learn Python - Python tutorial - Python Program to Reverse a Number - Python examples - Python programs

## OUTPUT Learn Python - Python tutorial - Python Program to Reverse a Number Using While Loop - Python examples - Python programs

## Analysis:

• This program allows the user to enter any positive integer and then, that number is assigned to variable Number.
• Next, Condition in the While loop will make sure that, the given number is greater than 0
• From the above example, User Entered value: Number = 1456 and Reverse = 0

## First Iteration

Reminder = Number %10
Reminder = 1456%10 = 6
Reverse = Reverse *10+ Reminder
Reverse = 0 * 10 + 6
Reverse = 0 + 6
Reverse = 6
Number = Number //10
Number = 1456 //10
Number = 145

## Second Iteration

From the first Iteration the values of both Number and Reverse has been changed as:
Number = 145 and Reverse = 6
Reminder = Number % 10
Reminder = 145 % 10 = 5
Reverse = Reverse *10+ Reminder
Reverse = 6 * 10 + 5
Reverse = 60 + 5
Reverse = 65
Number = Number //10
Number = 145 //10
Number = 14

## Third Iteration

From the Second Iteration the values of both Number and Reverse has been changed as:
Number = 14 and Reverse = 65
Reminder = Number %10
Reminder = 14%10 = 4
Reverse = Reverse *10+ Reminder
Reverse = 65 * 10 + 4
Reverse = 650 + 4
Reverse = 654
Number = Number //10
Number = 14//10
Number = 1

## Fourth Iteration

From the Second Iteration the values of both Number and Reverse has been changed as:
Number = 1 and Reverse = 654
Reminder = Number %10
Reminder = 1 %10 = 1
Reverse = Reverse *10+ Reminder
Reverse = 654 * 10 + 1
Reverse = 6540 + 1
Reverse = 6541
Number = Number //10
Number = 1//10
Number = 0

• Here, For the next iteration Number = 0 so, the while loop condition will fail

## Python Program to Reverse a Number Using Functions

• This program allows the user to enter any positive integer and then, we are going to reverse a number using Python Functions

## OUTPUT Learn Python - Python tutorial - Python Program to Reverse a Number Using Functions - Python examples - Python programs

## ANALYSIS:

• When the compiler reaches to Reverse = Reverse_Integer (Number) line in the program then the compiler will immediately jump to below function:
• We already explained the code LOGIC in the above example. Please refer Python Program to Reverse an Integer Using While Loop Analysis.
• Last line ends with return Reverse statement.

Python program to find area of circle.

## Python Program to Reverse a Number using Recursion

• This program allows the user to enter any positive integer and then, we are going to reverse a number using Python Recursion

## OUTPUT Learn Python - Python tutorial - Python Program to Reverse a Number using Recursion - Python examples - Python programs

## ANALYSIS:

• When the compiler reaches to Reverse = Reverse_Integer (Number) line in the program then the compiler will immediately jump to below function:
• In this function, below statement will 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, Number = 459 will produce the output as 9
• Lets see the Python If Statement, if (Number > 0) will check whether the number is greater than 0 or not. For Recursive functions it is very important to place a condition before using the function recursively otherwise, we will end up in infinite execution (Same like infinite Loop).