Question

write a program to check whether a string is palindrome or not​

Answer 1

Following is C implementation to check if a given string is palindrome or not.

// A function to check if a string str is palindrome  

void is Palindrome(char str[])  

{  

   // Start from leftmost and rightmost corners of str  

   int l = 0;  

   int h = strlen(str) - 1;  

 

   // Keep comparing characters while they are same  

   while (h > l)  

   {  

       if (str[l++] != str[h--])  

       {  

           printf("%s is Not Palindrome", str);  

           return;  

       }  

   }  

   printf("%s is palindrome", str);  

}  

 

// Driver program to test above function  

int main()  

{  

   isPalindrome("abba");  

   isPalindrome("abbccbba");  

   isPalindrome("comp");  

   return 0;  

}

Output:

abba is palindrome

abbccbba is palindrome

comp is Not Palindrome

Answer 2

s = input("Enter a string: ")

if s[0:] == s[::-1]:

   print("The string is a palindrome.")

else:

   print("The string isn't a palindrome.")

The above program can be done using string slicing.

String slicing is the act of extracting a substring from a given string. In order to do so, one must understand how to declare each character's index values.

• Positive indexing starts traversing through the string forwards and starts with the index value 0.
• Negative indexing starts traversing through the string backwards and starts with the index value -1.

When you give a negative number as the step value, the string is read in its reverse order.