Recover

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

int main(int argc, char *argv[]) {

//check proper command line usage
if (argc != 2)
    {
        fprintf(stderr, "Usage: ./recover FILE\n");
        return 1;
    }


//open input file
FILE *inptr = fopen(argv[1], "r");


//check for valid file
if(inptr == NULL)
    {
        fprintf(stderr, "Invalid File %s.\n", argv[1]);
        return 2;
    }
    
    
//declare file for images
FILE *img = NULL;

//counter for jpg name
int i = 0;


//loop until end of file found
do{
    
    
    
    //read input file
    unsigned char store[512];
    fread(store, 512, 1, inptr);
    
    
    //check for start of JPEG
     
     if (store[0] == 0xff &&
        store[1] == 0xd8 &&
        store[2] == 0xff &&
        (store[3]  &0xf0) == 0xe0)
        
        {
        
            //check if alrady found a JPEG
        
            if (img == NULL)
            {
                
                //print string for jpg name
                char filename[50];
                sprintf(filename, "%03i.jpg", i);
                
            
                //open jpg for output
                img = fopen(filename, "w");
            
            
                //write to new jpg
                fwrite(store, 512, 1, img);
            }
        
        
            else
            {
                //close open jpg
                fclose(img);
            
            
                //add to jpg name
                i++;
            
            
                //print string for jpg name
                char *filename = NULL;
                sprintf(filename, "%03i.jpg", i);
            
            
                //open jpg for output
                img = fopen(filename, "w");
            
            
                //write to new jpg
                fwrite(store, 512, 1, img);
            }
        }
    
        
    else
    {
        //check if already found jpg
        if(img == NULL)
        {
            //exit loop to check next 512 bytes
            break;
        }
        
        else
        {
            
            //write to open jpg
            fwrite(store,512, 1, img);
            
        }
        
    }
                    
    
    }
    while (fread >0);
    
    
 //close input file 
 fclose(inptr);
 
 //close jpg file
 fclose(img);
 
 
 
 //return success
 return 0;

}