#include <fstream.h>
#include <stdio.h>

// This program reads the Bit Data Offset field.
// Note that b0 is the least significant digit,
// occupying the lowest address in memory

// For further reference, please read:
// http://www.cs.umass.edu/~verts/cs32/endian.html
// Thanks to Darrell Grainger for the contribution
// in the newsgroup with this link

int main(int argc, char* argv[])
{
 fstream fs;
 unsigned char b0, b1, b2, b3;
 int value;

 // Open as binary
 fs.open("1.bmp", ios::in|ios::binary);

 // Positions the get pointer to read the "Offset" field
 fs.seekg(2 + 4 + 4);
// fs.seekg(2); // For the file size (24750) - Comment the previous line

 // Reads the next four bytes
 // The value of b0..b3 are already in decimals
 fs.read((char*)&b0, sizeof(char));
 fs.read((char*)&b1, sizeof(char));
 fs.read((char*)&b2, sizeof(char));
 fs.read((char*)&b3, sizeof(char));

 // Calculates the value
 value = b0 + 256*b1 + 256*256*b2 + 256*256*256*b3;

 cout << "Bit Data Offset = " << value << endl;

 fs.close();

 cout << "Press any key to close" <<  endl;
 getchar();

 return 0;
}