Palindrome Program in Python

In this article, we will show you, How to write a Palindrome Program in Python using While Loop, Functions and Recursion.

Palindrome

Any number can be Palindrome, if it is remained same when we reversed it. For example 131 is a palindrome number because, this number remains same after reversing it. Following steps will show you the common approach to check for the Palindrome Number

Steps

1. Enter any number
2. Reverse a given number
3. Compare original value with reverse value.
4. If they exactly matched then it is Palindrome number otherwise it is not Palindrome number.

Palindrome Program in Python using While Loop

This python program allows the user to enter any positive integer. Next, this program will check whether a given number is Palindrome Number or Not using While Loop

# Python Palindrome Program using While loop
 
number = int(input("Please Enter any Number: "))

reverse = 0
temp = number

while(temp > 0):
    Reminder = temp % 10
    reverse = (reverse * 10) + Reminder
    temp = temp //10
 
print("Reverse of a Given number is = %d" %reverse)

if(number == reverse):
    print("%d is a Palindrome Number" %number)
else:
    print("%d is not a Palindrome Number" %number)

OUTPUT

ANALYSIS:

User Entered value: Number = 191 and Reverse = 0
Temp = Number
Temp = 191

First Iteration
Reminder = Temp %10
Reminder = 191 % 10 = 1

Reverse = Reverse *10 + Reminder
Reverse = 0 * 10 + 1
Reverse = 0 + 1
Reverse = 1

Temp = Temp //10
Temp = 191 /10
Temp = 19

Second Iteration
From the first Iteration the values of both Temp and Reverse has been changed as:
Temp = 19 and Reverse = 1

Reminder = 19 % 10 = 9

Reverse = 1 * 10 + 9
Reverse = 10 + 9
Reverse = 19

Temp = 19 /10
Temp = 1

Third Iteration
From the Third Iteration the values of both Temp and Reverse has been changed as:
Temp = 1 and Reverse = 19

Reminder = 1 % 10 = 1

Reverse = 19 * 10 + 1
Reverse = 190 + 3
Reverse = 191

Temp = 1/10
Temp = 0

Here Number = 0 so, the while loop condition will fail

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

Palindrome Program in Python using Functions

In this program we defined a function. Within that function, we used If statement.

# Python Palindrome Program using Functions
 
reverse = 0
def integer_reverse(number):
    global reverse
    
    if(number > 0):
        Reminder = number % 10
        reverse = (reverse * 10) + Reminder
        integer_reverse(number // 10)
    return reverse


number = int(input("Please Enter any Number: "))

rev = integer_reverse(number)
print("Reverse of a Given number is = %d" %rev)

if(number == rev):
    print("%d is a Palindrome Number" %number)
else:
    print("%d is not a Palindrome Number" %number)

OUTPUT

Palindrome Program in Python using Recursion

In this program we are checking whether a given number is Palindrome Number or Not using Recursive Functions concept.

# Python Program to print Palindrome numbers from 1 to 100
 
maximum = int(input(" Please Enter the Maximum Value : "))

print("Palindrome Numbers between 1 and %d are : " %maximum)
for num in range(1, maximum + 1):
    temp = num
    reverse = 0
    
    while(temp > 0):
        Reminder = temp % 10
        reverse = (reverse * 10) + Reminder
        temp = temp //10

    if(num == reverse):
        print("%d " %num, end = '  ')

OUTPUT

ANALYSIS

In this function,

integer_reverse (Number // 10) – it 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 = 191 then the output will be 1

Lets see the If condition

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).

Please be careful :)