Saying code is not correct in code coach even though outputs are same

Question

Language: C
Code coach: EXTRA TERRESTRIAL
#include<stdio.h>
#include<string.h>
int main()
{
char str[50];
scanf("%s",&str);
int len,i;
len=strlen(str);
for(i=len;i>=0;i--){
printf("%c",str[i]);
}
return 0;
}
ANYONE TELL WHERE I DID THE MISTAKE

Answer 1

You are also displaying the NULL character which was there at the end of the string while printing the reverse string.
Start your loop from (len-1) to fix it 👇
https://code.sololearn.com/cK7x49lnSNMK/?ref=app