Palindrome Program in Python, C, C++, and Java [Beginner Guide]
Introduction
Palindrome numbers and strings are a common coding interview question asked in SRMU, BBD, Integral University, and many IT companies.
A palindrome is a number, string, or word that reads the same forward and backward.
Examples:
- Number:
121,1331 - Word:
madam,level,racecar
In this post, we will learn how to write a Palindrome Program in Python, C, C++, and Java using different approaches: Loop, Function, and Recursion.
Palindrome in Python
1. Using Loop
num = int(input("Enter a number: "))
temp = num
rev = 0
while num > 0:
digit = num % 10
rev = rev * 10 + digit
num //= 10
if temp == rev:
print("Palindrome")
else:
print("Not Palindrome")Using Function
def is_palindrome(num):
return str(num) == str(num)[::-1]
n = int(input("Enter a number: "))
if is_palindrome(n):
print("Palindrome")
else:
print("Not Palindrome")Using Recursion
def is_palindrome(s):
if len(s) <= 1:
return True
if s[0] != s[-1]:
return False
return is_palindrome(s[1:-1])
s = input("Enter a string: ")
if is_palindrome(s):
print("Palindrome")
else:
print("Not Palindrome")Palindrome in C
1. Using Loop
#include <stdio.h>
int main() {
int num, temp, rev = 0, digit;
printf("Enter a number: ");
scanf("%d", &num);
temp = num;
while (num > 0) {
digit = num % 10;
rev = rev * 10 + digit;
num /= 10;
}
if (temp == rev)
printf("Palindrome\n");
else
printf("Not Palindrome\n");
return 0;
}
2. Using Function
#include <stdio.h>
int isPalindrome(int num) {
int temp = num, rev = 0, digit;
while (num > 0) {
digit = num % 10;
rev = rev * 10 + digit;
num /= 10;
}
return temp == rev;
}
int main() {
int n;
printf("Enter a number: ");
scanf("%d", &n);
if (isPalindrome(n))
printf("Palindrome\n");
else
printf("Not Palindrome\n");
return 0;
}3. Using Recursion
#include <stdio.h>
#include <string.h>
int isPalindrome(char str[], int start, int end) {
if (start >= end)
return 1;
if (str[start] != str[end])
return 0;
return isPalindrome(str, start + 1, end - 1);
}
int main() {
char str[100];
printf("Enter a string: ");
scanf("%s", str);
if (isPalindrome(str, 0, strlen(str) - 1))
printf("Palindrome\n");
else
printf("Not Palindrome\n");
return 0;
}Palindrome in C++
1. Using Loop
#include <iostream>
using namespace std;
int main() {
int num, temp, rev = 0, digit;
cout << "Enter a number: ";
cin >> num;
temp = num;
while (num > 0) {
digit = num % 10;
rev = rev * 10 + digit;
num /= 10;
}
if (temp == rev)
cout << "Palindrome";
else
cout << "Not Palindrome";
return 0;
}2. Using Function
#include <iostream>
using namespace std;
bool isPalindrome(int num) {
int temp = num, rev = 0, digit;
while (num > 0) {
digit = num % 10;
rev = rev * 10 + digit;
num /= 10;
}
return temp == rev;
}
int main() {
int n;
cout << "Enter a number: ";
cin >> n;
if (isPalindrome(n))
cout << "Palindrome";
else
cout << "Not Palindrome";
return 0;
}3. Using Recursion
#include <iostream>
using namespace std;
bool isPalindrome(string s, int start, int end) {
if (start >= end)
return true;
if (s[start] != s[end])
return false;
return isPalindrome(s, start + 1, end - 1);
}
int main() {
string str;
cout << "Enter a string: ";
cin >> str;
if (isPalindrome(str, 0, str.length() - 1))
cout << "Palindrome";
else
cout << "Not Palindrome";
return 0;
}Palindrome in Java
1. Using Loop
import java.util.Scanner;
public class PalindromeLoop {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter a number: ");
int num = sc.nextInt();
int temp = num, rev = 0, digit;
while (num > 0) {
digit = num % 10;
rev = rev * 10 + digit;
num /= 10;
}
if (temp == rev)
System.out.println("Palindrome");
else
System.out.println("Not Palindrome");
sc.close();
}
}2. Using Function
import java.util.Scanner;
public class PalindromeFunction {
static boolean isPalindrome(int num) {
int temp = num, rev = 0, digit;
while (num > 0) {
digit = num % 10;
rev = rev * 10 + digit;
num /= 10;
}
return temp == rev;
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter a number: ");
int n = sc.nextInt();
if (isPalindrome(n))
System.out.println("Palindrome");
else
System.out.println("Not Palindrome");
sc.close();
}
}3. Using Recursion
import java.util.Scanner;
public class PalindromeRecursion {
static boolean isPalindrome(String str, int start, int end) {
if (start >= end)
return true;
if (str.charAt(start) != str.charAt(end))
return false;
return isPalindrome(str, start + 1, end - 1);
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter a string: ");
String s = sc.next();
if (isPalindrome(s, 0, s.length() - 1))
System.out.println("Palindrome");
else
System.out.println("Not Palindrome");
sc.close();
}
}Conclusion
Palindrome programs are frequently asked in university exams (SRMU, BBD, Integral) and coding interviews at companies.
We covered Python, C, C++, and Java solutions using Loop, Function, and Recursion.
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