Recover.c in pset4 of cs50

Recover.c

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

int main(int argc,char *argv[])
{
    if(argc!=2)
    {
        fprintf(stderr,"usage: ./recover infile");
        return 1;
    }
    uint8_t block;
    int d=0;
    unsigned char data[512];
    char *buffer=argv[1];
    FILE *inptr=fopen(buffer,"r");
    if(inptr==NULL)
      {
        fprintf(stderr,"could not open %s",buffer);
        fclose(inptr);
        return 2;
      }
    char ch;
    size_t no;
    while(fread(data,(sizeof(block)),512,inptr)==512)
      {

        if(data[0]==0xff&&data[1]==0xd8&&data[2]==0xff&&(data[3]==0xe0||data[3]==0xe1))
          {
            char arr[8];

             sprintf(arr,"%03d.jpg",d);
             d++;
             FILE *img=fopen(arr,"w");
             do
             {
               fwrite(data,1,(sizeof(block)*512),img);
                   no= fread(data,sizeof(block),512,inptr);
                }


             while(((data[0]!=0xff) && (data[1]!=0xd8) && (data[2]!=0xff)) && ((data[3]!=0xe0) || (data[3]!=0xe1))&&(no==512));
               ch=fgetc(inptr);
              printf("%c",ch);

            fclose(img);
            fseek(inptr,-(sizeof(block)*512),SEEK_CUR);

          }

    }
    fclose(inptr);
    return 0;
}