please check my code and solve the error?

Question

 

 here i write a program to check the given string is plindrome or not by using recursion function.iam getting exception here please solve it.

 

 

 

 

 

 

 

 

 

 

using System;

using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


namespace prime
{
class Program
{
public static void Main()
{

Program p = new Program();

Console.WriteLine("enter a string");

string s1 = Console.ReadLine();

//string s1 ="madam";

char[] str = s1.ToCharArray();

Console.WriteLine( p.ispalindrome(str));
Console.ReadLine();


}
int ispalindrome(char[] str)
{

char[] s = new char[str.Length - 2];
if(str.Length==0||str.Length==1)
return 1;

if(str[0]==str[str.Length-1])
{
int k = 1;

for(int j=0;j<str.Length-2;j++)
{
s[j]=str[k];
k++;
}
return ispalindrome(s);

}




else
{
return 0;
}

}

}

}