Complete the code for -- isPalindromeHelper(const char *s1, int len); bool isPal

Question

Complete the code for --

isPalindromeHelper(const char *s1, int len);

bool isPalindrome(const char *s1);

#include #include #include #include "include "strFuncs.h" using namespace std; bool isPalindromeHelper (const char *s1, int len); /Precondition: s1 is a valid C-string that may contain upper or lower case alphabets, no spaces or special characters //Postcondition: Returns true if s1 is a palindrome, false otherwise //You MUST provide a recursive implementation and are recommended to write a helper function where the recursion actually takes place* bool isPalindrome(const char s1)

Explanation / Answer

bool isPalindrome(char *str)

{

int n = strlen(str);

// An empty string is considered as

// palindrome

if (n == 0)

return true;

return isPalindromeHelper(str, n);

}

bool isPalindromeHelper(const char *s1, int len){

// If there is only one character

if (len <= 1)

return true;

// If first and last characters do not match

if (*s1 != *(s1+len-1))

return false;

// If there are more than two characters,

// check if middle substring is also

// palindrome or not.

return isPalindromeHelper(++s1, len-1);

return true;

}

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