c++ - Reading binary data into struct with ifstream

Question

I'm trying to read binary data from a file using ifstream.

Specifically, I'm trying to populate this "Header" struct with data read from a file:

struct Header {
    char id[16];
    int length;
    int count;
};

1. Now, if I read the file in this way, the result is exactly what I want:

   input.read((char*)&hdr, sizeof(hdr));
   

2. But if I instead read each variable of the struct manually, the results are gibberish:

   input.read((char*)&hdr.id,     sizeof(hdr.id));
   input.read((char*)&hdr.length, sizeof(hdr.length));
   input.read((char*)&hdr.count,  sizeof(hdr.count));
   

My question is, what is happening here that makes these two methods return different results?

Answer 1

It is also possible to read the struct in one step.

i.e. fh.read((char*)&h, sizeof(Header));