pset4 recover.c sigmentation fault

Question

guys i dont know why but i have sigmentation fault help please

/**
 * recover.c
 *
 * Computer Science 50
 * Problem Set 4
 *
 * Recovers JPEGs from a forensic image.
 */
 #include<stdio.h>
 #include<cs50.h>
 #include<stdlib.h>
 #include<stdint.h>
 #include<string.h>

int main(void)
{
    FILE *fp = fopen("card.raw","r");
    if(fp == NULL)
    {
        fclose(fp);
        {
            printf("cant open file\n");
            return 1;
        }
    }
    FILE *outptr;
    int jpgcount = 0;
    uint8_t buffer[512];
    {
        fread(buffer,512,1,fp);
    }
    while(fread(buffer, 512, 1, fp) > 0)
    {
        if(buffer[0] == 0xff &&
        buffer[1] == 0xd8 &&
        buffer[2] == 0xff &&
        (buffer[3] == 0xe0 || buffer[3] == 0xe1))
        {
            {
                fclose(outptr);
                jpgcount++;
            }
            char filename[8];
            {
                sprintf(filename,"%03i.jpg",jpgcount);
            }
            {
                    outptr = fopen(filename, "w");
                    fwrite(buffer, sizeof(buffer), 1, outptr);
            }
        }
    }
        fclose(outptr);
        fclose(fp);
        return 0;
}    

Answer 1

The seg fault is being caused by the following line inside the while loop:

fclose(outptr);

The reason is that the first file hasn't been opened yet. But since you've already moved on to other issues, I'll assume that you found the problem. ;-)

If this answers your question, please click on the check mark to accept. Let's keep up on forum maintenance. ;-)

Answer 2

The line 20 ("fclose(fp);") is odd, try to remove it. You cannot close a file when it was not opened.