i thought i got the main idea with my pseudocode and actually it opens the exact amount of files in the "card.raw" but when i try to open them none of them opens and gives "invalid or unsupported Image format" error.Can someone help me to spot what am i doing wrong ?

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

typedef uint8_t  BYTE;

int main(int argc, char* argv[])
// global variable to count array for title
int jpg = 0;
FILE* img = NULL;

// open card file
FILE* inptr = fopen("card.raw", "r");
if (inptr == NULL)
    printf("couldn't open the file\n");
    return 1;

// temporary storage for buffering
BYTE buffer[512];

// repeat until end of card file
while (!feof(inptr)) 
    // read 512 bytes into a buffer
    fread(&buffer, 512 * sizeof(BYTE), 1, inptr);

    // check if its a start of a new jpg
    if (buffer[0] == 0xff && buffer[1] == 0xd8 && buffer[2] == 0xff && (buffer[3] == 0xe0 || buffer[3] == 0xe1))
        // check if there is an image file open to close it
        if (img != NULL)
        // temporary storage for title buffer
        char title[3];

        // make title names for each new jpg
        sprintf(title, "%.3d.jpg", jpg);

        // open a new file 
        img = fopen(title, "a");
        if (img == NULL)
            printf("couldn't open the new image file\n");
            return 2;
        //update the counter

    // check if its already a jpg
    if (img != NULL)
        //write to the newfile
        fwrite(&buffer, 512 * sizeof(BYTE), 1, img);
//close the files
return 0;



You are declaring title with length 3, which will hold 2 chars and the end of string marker. You then try to stuff a 7 character filename in it. This is messing up the filenames. title needs to be sufficiently long to correctly hold the file name string plus the end of string marker.

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  • thanks a lot it worked but now my only problem is even if i had the 16 images looking correct the last one of them is giving error on check50. – Erkan Apaydın Dec 8 '15 at 9:23
  • ok i made it work totally after deleted fread line in the loop and changed the whi condition to that fread line equals one. – Erkan Apaydın Dec 8 '15 at 10:30

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