PSET4 Recover - Code gets stuck at if statement

Question

I'm working on the recover problem, but when my code gets to the if statement I made that checks for the header of a JPEG file, it gets stuck.

I get no errors, it simply stops iterating through the loop. I also found that when I printed out the integer values of the first four elements of the array they were all 0.

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

typedef uint8_t BYTE;

int main(int argc, char *argv[])
{
    // Make sure only one argument is given
    if (argc != 2)
    {
        printf("Usage: ./recover image");
        return 1;
    }

    // Open file with given argument
    FILE* file = fopen(argv[1], "r");
    // Return from main if there is no file with that name
    if (file == NULL)
    {
        printf("Usage ./recover image");
        return 1;
    }

    // Initialize variables
    BYTE arr[512];
    bool fileOpen = false;
    FILE* ptr;
    int n = 0;
    char filename[7];
    // Loop
    printf("loop reached\n");
    while(1 == 1)
    {
        // Read 512 bytes to array 'arr'
        printf("iteration\n");
        fread(arr, sizeof(BYTE), 512, file);

        // If the end of the file has been reached, break the loop
        if (feof(file))
        {
            printf("broken\n");
            break;
        }
        // Check for JPEG header
        if (arr[0] == 0xff && arr[1] == 0xd8 && arr[2] == 0xff && (arr[3] & 0xf0) == 0xe0)
        {
            if (fileOpen)
            {
                // Close last file
                fclose(ptr);
            }

            // Create filename
            if (n < 10)
            {
                sprintf(filename, "00%i.jpg", n);
            }
            else if (n < 100)
            {
                sprintf(filename, "0%i.jpg", n);
            }
            else
            {
                sprintf(filename, "%i.jpg", n);
            }
            ptr = fopen(filename, "a");

            // Write to the file
            fwrite(arr, sizeof(BYTE), 512, ptr);

            // A file is open
            n++;
            fileOpen = true;
        }
        else
        {
            fwrite(arr, sizeof(BYTE), 512, ptr);
        }
    }
    // Close the file
    fclose(file);
}

Answer 1

Solved; turns out it was stuck at the else statement because it was trying to write to a file using a pointer that had not been declared. Fixed it by adding an if statement and only writing if fileOpen is true.