Palindrome code

[ShawnWalker]

Hello everybody,
I have written a small source code for determining whether the string is a palindrome or not.I just want your comments on it.In this code i am not getting benefit of recursion as i think.Can anybody correct it so that it can take advantage of recursion.
thanks in advance
shawnwalker

#include <iostream.h>
#include <string.h>
#include <conio.h>
 
char * a="abcdecba";
int len = strlen(a)-1;
int index = 0;
int recursiveCallNo = len/2;
 
int palin(char * strUserInput) 
{
 
    if (strUserInput[index] == strUserInput[len])
    {
        index++;
        len--;
        if (index <=recursiveCallNo)
        return palin(strUserInput);
    }
 
    else
        return -1;        
}
 
 
void main() 
{    
    cout << palin(a)<<endl;
}

[Ganon11]

It's certainly a different method than I would take, but it appears to work as you wanted - except if the string actually is a palindrome. You are telling it to return palin(strUserIn put) in the case that the last and first characters are equal, but what if the first and last characters are equal, yet index is past the recursiveCallNo variable? In this case, nothing is returned, but I believe you want to return 1.