Given a string, write a c function to check if it is palindrome or not.
A string is said to be palindrome if reverse of the string is same as string. For example, “abba” is palindrome, but “abbc” is not palindrome.
Algorithm:
isPalindrome(str)
1) Find length of str. Let length be n.
2) Initialize low and high indexes as 0 and n-1 respectively.
3) Do following while low index ‘l’ is smaller than high index ‘h’.
…..a) If str[l] is not same as str[h], then return false.
…..b) Increment l and decrement h, i.e., do l++ and h–.
4) If we reach here, it means we didn’t find a mis
Following is C implementation to check if a given string is palindrome or not.
#include <stdio.h> #include <string.h> // A function to check if a string str is palindrome void isPalindrome(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("geeks"); return 0; } |
Output:
abba is palindrome abbccbba is palindrome geeks is Not Palindrome
Recursive function to check if a string is palindrome
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