Aim:

Design, develop and execute a program in C to reverse a given four digit integer number and check whether it is a palindrome or not. Output the given number with suitable message.

Summary:

Palindrome is a number, word, phrase, or sequence that reads the same backward as forward, e.g., "madam" or "malayalam" or 1221 or 10301.

Algorithm:

1. Start.
2. Take a four digit number as input i.e. n.
3. Assign value of n to m (to retain the value of n)

4. Until the value of n is not 0.

      Do    
      rem=n%10;        
      rev=rev*10+rem;
      n=n/10;
   

5. When value of m is equal to rev, go to step 6, else to 8.

6. Print given number as palindrome, goto step 8
7. Print given number as not palindrome.
8. Stop.

Program: Palindrome.c

#include<stdio.h>
void main()
{
    int n,m,rem,rev=0;
    printf("Enter the number\n");
    scanf("%d",&n); // taking input //
    m=n;   // assigning value of n to m //
    while(n!=0)
    {                  //reversing the integer //
        rem=n%10;        
        rev=rev*10+rem;
        n=n/10;
    }

    printf("The reverse of %d is %d\n",m,rev);  
           // printing the reversed integer //

    if(m==rev)  //executes when reversed integer is same as given integer //
        printf("It is a palindrome\n");
    else   // executes when not equal //
        printf("It is not a palindrome\n");
}

Output:

Run the following commands in your terminal:

gcc palindrome.c

./a.out

    1. Enter the number
       7667
       Reverse of 7667 is 7667
       It is a palindrome

gcc palindrome.c

./a.out

   2.  Enter the number
       1234
       Reverse of 1234 is 4321
       It is not a palindrome