Palindrome number program
In this post, you will learn how to write program to check whether a number is palindrome or not in different programming languages.
A palindrome is a number, string, or sequence that remains the same when it is reversed. A palindrome sequence can be a combination of digits or numbers, but it looks the same going forward and backward. It is generally used where recreational mathematics is applied, like- puzzles, games. To check whether a number or string is palindrome or not, simply reverse it and compare it with the original number or string. If both are same then the number or string is a palindrome, otherwise not.
These are the some examples of Palindrome numbers and strings-
121, 1991, 1239321, MAAM, DAD, WOWWhen we reverse the above numbers or strings this will remain the same. So, all the above are palindromes.
C program to check palindrome using recursion
A Recursion function is a function that is called itself. In the given example, we call the recursion function to check the palindrome. A recursion function continues until some condition is met to prevent it. That's why, we use the if else statement to break the infinite recursion. Here, we have used a user defined recursion function is_palindrome() to check whether the given number is palindrome or not.
#include<stdio.h>
int is_palindrome(int num){
static int rev_num=0,rem;
if(num!=0){
rem = num%10;
rev_num = rev_num*10+rem;
is_palindrome(num/10);
}
return rev_num;
}
int main(){
int num, rev_num;
printf("Please enter a number : ");
scanf("%d",&num);
rev_num = is_palindrome(num);
if(num == rev_num)
printf("%d is a palindrome number.",num);
else
printf("%d is not a palindrome number.",num);
return 0;
}Please enter a number : 4566654
4566654 is a palindrome number.Python program to check Palindrome numbers using While loop
In the given code, we have some numbers in the list. We have used the while loop and reverse each integer and compare it with original number to check whether it is a palindrome or not.
data = [121, 1991, 1239, 343343, 28981]
for x in data:
temp = int(x)
rev = int()
while(temp > 0):
d = temp % 10
rev = (rev * 10) + int(d)
temp = temp//10
if(rev == x):
print("{} is a Palindrome".format(x))
else:
print("{} is not a Palindrome".format(x))121 is a Palindrome
1991 is a Palindrome
1239 is not a Palindrome
343343 is a Palindrome
28981 is not a PalindromePython program to check Palindrome strings using slice operator
The slice operator is in the format [n:m], which returns a slice of the string from the nth character to the mth character. The first index is optional. If we omit the first index, i.e., before the colon, the slice starts at the beginning of the string. The [: m] will slice the list from starting till the mth index. That is why [: : -1] prints list in reverse order. The negative value shows right to left traversal.
Here is the Python program to check palindrome strings using the slicing operator. Simply, we first reverse each string using slice operator and compare it with the original string.
data = ['MAAM', 'SUPER', 'DAD', 'WOW', 'HAPPY']
for x in data:
if(x == x[::-1]):
print("{} is a palindrome".format(x))
else:
print("{} is not a palindrome".format(x))MAAM is a palindrome
SUPER is not a palindrome
DAD is a palindrome
WOW is a palindrome
HAPPY is not a palindromePHP program to check Palindrome using while loop
In the given PHP code, we have used the while loop to check the palindromes. For this, we defined a function 'Check_Palindrome()' and passed an array into it as an argument. We reversed the array element using the while loop and compared it with the original element. If equal, it means the string or number is a palindrome.
<?php
function Check_Palindrome($arr){
$temp = $arr;
$rev = 0;
while (floor($temp)) {
$d = $temp % 10;
$rev = $rev * 10 + $d;
$temp = $temp/10;
}
if ($rev == $arr){
return 1;
}
else{
return 0;
}
}
//Check Palindrome
$palindrome = array(121, 1991, 1239, 'MAAM', 'SUPER', 'DAD', 'WOW');
foreach($palindrome as $p){
if(Check_Palindrome($p)){
echo $p." is a Palindrome.<br/>";
}
else {
echo $p." is not a Palindrome.<br/>";
}
}
?>121 is a Palindrome.
1991 is a Palindrome.
1239 is not a Palindrome.
MAAM is a Palindrome.
SUPER is not a Palindrome.
DAD is a Palindrome.
WOW is a Palindrome.C++ program to check palindrome number using do while loop
In the given C++ program, we will get an input from the user and check whether number is palindrome or not.
#include <iostream>
using namespace std;
int main()
{
int val, num, digit, rev = 0;
cout << "Enter a positive number: ";
cin >> num;
val = num;
do
{
digit = num % 10;
rev = (rev * 10) + digit;
num = num / 10;
} while (num != 0);
cout << " The reverse of the number is: " << rev << endl;
if (val == rev)
cout << " The number is a palindrome.";
else
cout << " The number is not a palindrome.";
return 0;
}Enter a positive number: 124421
The reverse of the number is: 124421
The number is a palindrome.Related Articles
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