Palindrome Program in C

Palindrome

Any number can be Palindrome, if it is remained same when we reversed it. For example 191 is a palindrome number because, this number remains same even after reversing it. In this article we show you, How to write a Palindrome Program in C Programming to Check Whether the Number is Palindrome or Not Using While Loop, For Loop, Functions and Recursion. We will also show you the Palindrome Numbers between 1 to n. Following steps will show you the common approach to check for the Palindrome Number

Steps:

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

Palindrome Program in C Using While Loop

This C program allows the user to enter any positive integer and then, this program will check whether the given number is Palindrome Number or Not using the While Loop

/* Palindrome Program in C using While Loop */
#include <stdio.h>

int main()
{
   int Number, Temp, Reminder, Reverse = 0;
 
   printf("\nPlease Enter any number to Check for Palindrome\n");
   scanf("%d", &Number);
  
   //Helps to prevent altering the original value
   Temp = Number;

   while ( Temp > 0)
   {
      Reminder = Temp %10;
      Reverse = Reverse *10+ Reminder;
       Temp = Temp /10;
   }
 
   printf("Reverse of entered number is = %d\n", Reverse);

   if ( Number == Reverse )
      printf("\n%d is Palindrome Number.\n", Number);

   else
      printf("%d is not the Palindrome Number.\n", Number);
 
   return 0;
}

OUTPUT

ANALYSIS
This program allows the user to enter any positive integer and then, that number is assigned to variable Number.
Next, We assign the original value to the Temp variable. This will help us to preserve our original value and then do all the manipulation on Temp variable.
Next, Condition in the While loop will make sure that, the given number is greater than 0

User Entered value: Number = 1331 and Reverse = 0
Temp = Number
Temp = 1331

First Iteration
Reminder = Temp %10
Reminder = 1331%10 = 1

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

Temp = Temp /10
Temp = 1331 /10
Temp = 133

Second Iteration
From the first Iteration the values of both Temp and Reverse has been changed as: Temp = 133 and Reverse = 1
Reminder = Temp % 10
Reminder = 133 % 10 = 3

Reverse = Reverse *10+ Reminder
Reverse = 1 * 10 + 3
Reverse = 10 + 3
Reverse = 13

Temp = Temp /10
Temp = 133 /10
Temp = 13

Third Iteration
From the Third Iteration the values of both Temp and Reverse has been changed as: Temp = 13 and Reverse = 13
Reminder = Temp %10
Reminder = 13%10 = 3

Reverse = Reverse *10+ Reminder
Reverse = 13 * 10 + 3
Reverse = 130 + 3
Reverse = 133

Temp = Temp /10
Temp = 13/10
Temp = 1

Fourth Iteration
From the Fourth Iteration the values of both Temp and Reverse has been changed as: Temp = 1 and Reverse = 133
Reminder = Temp %10
Reminder = 1 %10 = 1

Reverse = Reverse *10+ Reminder
Reverse = 133 * 10 + 1
Reverse = 1330 + 1
Reverse = 1331

Temp = Temp /10
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

if ( Number == Reverse )
if(1331 ==1331) – TRUE
Palindrome

Palindrome Program in C Using For Loop

This program allows the user to enter any positive integer and then, this program will check whether the given number is Palindrome Number or Not using the For Loop

/* Palindrome Program in C using For Loop */
#include <stdio.h>

int main()
{
  int Number, Temp, Reminder, Reverse = 0;
 
  printf("\nPlease Enter any number to Check for Palindrome\n");
  scanf("%d", &Number);
   
  for(Temp = Number; Temp > 0; Temp =  Temp /10 )
  {
     Reminder = Temp %10;
     Reverse = Reverse *10+ Reminder;
  }
 
  printf("Reverse of entered number is = %d\n", Reverse);

  if ( Number == Reverse )
     printf("\n%d is Palindrome Number.\n", Number);

  else
     printf("%d is not the Palindrome Number.\n", Number);
 
  return 0;
}

OUTPUT

We just replaced the While loop in the above example with the For loop. If you don’t understand the for loop then please refer For Loop article here: For Loop in C Programming

Palindrome Program in C Using Functions

This program allows the user to enter any positive integer and then, this program will check whether the given number is Palindrome Number or Not using Functions concept.

/* Palindrome Program in C using Functions */
#include <stdio.h>

int Reverse_Integer (int)

int main()
{
  int Number, Reverse = 0;
 
  printf("\nPlease Enter any number to Check for Palindrome\n");
  scanf("%d", & Number);
 
  Reverse = Reverse_Integer (Number)

  printf("Reverse of entered number is = %d\n", Reverse);

  if ( Number == Reverse )
     printf("\n%d is Palindrome Number.\n", Number);
  else
     printf("%d is not the Palindrome Number.\n", Number);
 
  return 0;
}

int Reverse_Integer (int Number)
{
  int Reminder, Reverse = 0;

  for(; Number > 0; Number =  Number /10 )
   {
     Reminder = Number %10;
     Reverse = Reverse * 10 + Reminder;
   }

  return Reverse;
}

OUTPUT

ANALYSIS
When the compiler reaches to Reverse_Integer (Number) line in main() program then the compiler will immediately jump to below function:

int Reverse_Integer (int Number)

We already explained LOGIC above example. Please refer C Program to Check Whether a Number is Palindrome or Not Using While Loop Analysis section.

Last line ends with return Reverse statement.

NOTE: If we create a function with Void then there is no need to return any value but, if we declared a function with any data type (int, float etc) then we have return something out from the function.

Palindrome Program in C Using Recursion

This program allows the user to enter any positive integer and then, this program will check whether the given number is Palindrome Number or Not using Recursive Functions concept.

/* Palindrome Program in C using Recursion */
#include <stdio.h>

int Reverse_Integer (int)

int main()
{
  int Number, Reverse = 0;
 
  printf("\nPlease Enter any number to Check for Palindrome\n");
  scanf("%d", & Number);
 
  Reverse = Reverse_Integer (Number)

  printf("Reverse of entered number is = %d\n", Reverse);

  if ( Number == Reverse )
     printf("\n%d is Palindrome Number.\n", Number);
  else
     printf("%d is not the Palindrome Number.\n", Number);
 
  return 0;
}

int Reverse_Integer (int Number)
{
  static Reminder, Reverse = 0;
 
  if (Number > 0)
   {
     Reminder = Number %10;
     Reverse = Reverse *10+ Reminder;
     Reverse_Integer (Number /10);
     return Reverse;
   }
  else
     return 0;
}

OUTPUT

ANALYSIS
When the compiler reaches to Reverse_Integer (Number) line in main() program then the compiler will immediately jump to below function:

int Reverse_Integer (int Number)

In this function,

Reverse_Integer (Number /10); 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 = 1331

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 🙂

C Program for Palindrome Numbers between 1 and 1000

This program allows the user to enter minimum and maximum values. This program will finds the Palindrome Number between the Minimum and Maximum values.

#include<stdio.h>

int main()
{
  int Number,Reminder,Reverse,Temp;
  int Minimum,Maximum;

  printf("\nPlease Enter the Minimum & Maximum Values\n");
  scanf("%d %d",&Minimum, &Maximum);

  printf("Palindrome numbers Between %d and %d are:\n",Minimum, Maximum);

  for(Number=Minimum;Number<=Maximum;Number++)
   {
     Temp=Number;
     Reverse =0;
     while (Temp > 0)
      {
        Reminder =  Temp %10;
        Reverse = Reverse *10+ Reminder;
        Temp =  Temp /10;
      }
   if(Number==Reverse)
      printf("%d ",Number);
   }
 return 0;
}

OUTPUT

ANALYSIS
This program allows the user to enter minimum and maximum values.

for (Number=Minimum; Number<=Maximum; Number++)

This For Loop helps compiler to iterate between Minimum and Maximum Variables, iteration starts at the Minimum and then it iwill not exceed Maximum variable.

if(Number==Reverse) -– condition will check whether the iteration 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.

If this condition is True then, below statement will be printed

printf("%d ",Number);

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