Recover check50 says expected 000.jpg to exist

Question

I need some tips! I'm stuck on pset4 recover with a strange error message on check50, which returns:

:) recover.c exists 
:) recover.c compiles 
:( recovers 000.jpg correctly \ expected 000.jpg to exist 
:( recovers middle files correctly \ expected 001.jpg to exist 
:( recovers last file correctly \ expected 015.jpg to exist

However, when I run the program I can get all the jpgs and they show correct pictures. I have checked the name of jpg, it is three digit numbers.I wrote those codes to define the title:

char title[8];
sprintf(title,"%03d.jpg",i);

Does anyone know what the problem is? this is the code:

#include<cs50.h>
#include<stdlib.h>
#include <stdio.h>
#include <stdint.h>

uint8_t buffer[512];
int main(int argc, char* argv[])
{
    if (argc != 2)
    {
        return 0;
    }
    char* infile = argv[1];
    FILE* inptr = fopen(infile, "r");
    if (inptr == NULL)
    {
        printf("Could not open %s.\n", infile);
        return 1;
    }
    int i = 0;
    FILE* img = NULL;
    while(fread(buffer,512,1,inptr)==1)
    {
         while (buffer[0] == 0xff && buffer[1] == 0xd8 && buffer[2] == 0xff&& 0xef >= buffer[3] && 0xe0 <= buffer[3])
         {
              char title[8];
              sprintf(title,"%03d.jpg",i);
              if(img != NULL)
              fclose(img);
              img = fopen(title,"a");
              fwrite(buffer, 512, 1, img);
              while(fread(buffer,512,1,inptr)==1)
              {
                    if(buffer[0] == 0xff && buffer[1] == 0xd8 && buffer[2] == 0xff&& 0xef >= buffer[3] && 0xe0 <= buffer[3])
                    {
                         i = i+1;
                         break;
                     }
                    fwrite(buffer, 512, 1, img);
               }
         }
   }
   fclose(img);
   fclose(inptr);
   return 0;

}

Answer 1

You need to read this part of the pset specification again:

If this solves your problem, please click the green check mark to accept the answer.