C program to find a string is palindrome or not

In this article we will try to implement a C program to find a string is palindrome or not. A C program is provided below to check if the given string is a palindrome or not.

The program is:

/*
 * C program to implement the following string functions using user defined functions:
 * i. Length of a string
 * ii. Find whether the given string is a palindrome or not
 * Author: P.S.SuryaTeja
*/
#include <stdio.h>
#include <conio.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>

void length(char *str)
{
	int count = 0;
	while(*str != '\0')
	{
		count++;
		str++;
	}
	printf("\nLength of the string is: %d", count);
}

void ispalindrome(char *str)
{
	char *revstr, *startstr;
	int stringlength = strlen(str);
	int i, flag = 0;
	startstr = str;
	for(i = 0; i < stringlength - 1; i++)
		str++;
	revstr = str;
	while(startstr < revstr)
	{
		if(*startstr != *revstr)
			flag = 1;
		startstr++;
		revstr--;
	}
	if(flag == 0)
		printf("\nEntered string is a palindrome");
	else
		printf("\nEntered string is not a palindrome");
}

int main(int argc, char **argv)
{
	char str[20];
	printf("Enter a string: ");
	gets(str);
	printf("\n");
	length(str);
	printf("\n");
	ispalindrome(str);
    getch();
    return 0;
}

Input and output for the above program is as follows:

Enter a string: madam

Length of the string is: 5

Entered string is a palindrome

Suryateja Pericherla

Suryateja Pericherla, at present is a Research Scholar (full-time Ph.D.) in the Dept. of Computer Science & Systems Engineering at Andhra University, Visakhapatnam. Previously worked as an Associate Professor in the Dept. of CSE at Vishnu Institute of Technology, India.

He has 11+ years of teaching experience and is an individual researcher whose research interests are Cloud Computing, Internet of Things, Computer Security, Network Security and Blockchain.

He is a member of professional societies like IEEE, ACM, CSI and ISCA. He published several research papers which are indexed by SCIE, WoS, Scopus, Springer and others.