"Palindrome recursive function" detects palindromes right but doesn't behave as expected

I made a recursive function in C that prints whather entered string is palindrome or not. It gives correct answers,but left and right pointers have weird values,and printf prints 4 times for string "ana" instead of 2.Can someone explain me what is going on.

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/*run this program using the console pauser or add your own getch, system("pause") or input loop */
int palindrome(int left, int right, char string[])
{
    printf("stringleft:%c,stringright:%c,Left:%d,right:%d\n", left, right, string[left], string[right]);
    if (left == right)
    {
        return 1;
    }

    if (string[left] != string[right])
    {
        return 0;
    }

    left++;
    right--;

    palindrome(left, right, string);
}

int main(int argc, char *argv[])
{
    char s[20];
    int right = 0;
    printf("Please input the string:");
    scanf("%s", s);
    while (s[right] != '\0')
    {
        right++;
    }

    right--;
    printf("Right:%d\n", right);
    if (palindrome(0, right, s))
    {
        printf("\nEntered string is palindrome!  %d", palindrome(0, right, s));
    }
    else
    {
        printf("\nEntered string is not palindrome. %d", palindrome(0, right, s));
    }
}

I expected for string "ana"

left=0,right=2,string[left]=a,string[right]=a;
left=1,right=1,string[left]=n,string[right]=n;

The mistake is in your printf function

printf("stringleft:%c,stringright:%c,Left:%d,right:%d\n", string[left], string[right], left, right);

You should be passing string[left] and string[right] first and only then left and right.

Also, you have a slight mistake in your if statement:

if(left >= right){
        return 1;
}

Change it to this, so if you get an input with even length, like anna

You would still correctly finish your method

The reason why you get 4 outputs is because you call your palindrome method twice in if(palindrome(0,right,s)) and also inside if and else