To determine if the given string is a palindrome or not

Description:

if the reverse of a string is equal to original string then it is called palindrome

Algorithm:

Step 1:start

Step 2: read the string

Step 3: store reverse of the given string in a temporary string

Step 4: compare the two strings

Step 5: if both are equal then print palindrome

Step 6: otherwise print not palindrome

Step 7: stop

 Program:

#include<stdio.h>

#include<string.h>

enum Boolean{false,true};

enum Boolean IsPalindrome(char string[])

{

            int left,right,len=strlen(string);

            enum Boolean matched=true;

 if(len==0)

  return 0;

  left=0;

            right=len-1;

             /* Compare the first and last letter,second & second last & so on */

             while(left<right&&matched)

  {

   if(string[left]!=string[right])

                         matched=false;

                         else

                        {

                                     left++;

                                    right--;

                        }

            }

  return matched;

 }

int main()

{

  char string[40];

  clrscr();

  printf("****Program to test if the given string is a palindrome****\n");

  printf("Enter a string:");

  scanf("%s",string);

  if(IsPalindrome(string))

  printf("The given string %s is a palindrome\n",string);

  else

  printf("The given string %s is not a palindrome\n",string);

  getch();

  return 0;

}

Output:

1. Enter the string:malayalam

     The given string malayalam is a palindrome

2. Enter the string:india

    The given string india is not a palindrome

Conclusion: The program is error free

VIVA QUESATIONS:

1)      What is meant by palindrome ?

Ans: If the reverse of a string/number is equal to original string/ number then it is  

called palindrome.

2)      What is the use of gets() function ?

Ans: To read the string at a time

3)       What is the use of puts() function ?

Ans: To write the string at a time