How msg.sender changes through relaying function calls?

Question

I'm confused about how msg.sender changes through relaying function calls. I know that msg.sender sets to the caller(it should be me) address at first, but through the process, msg.sender can change to contract address. Like when one contract calls the function of the another contract, then the function of the another contract's msg.sender should be the first contract. Now, if like this,

contract example1 {
  function A() {
    print msg.sender; // just fake code to imagine it prints out the result
    example2.B();
  }
}

contract example2 {
  function B() {
    print msg.sender; 
    C();
  }
  function C() { print msg.sender; }
}

If I call function A(), then it will print my address, and followed by the process, B() will print contract example1's address. Then is C() will print contract example1's address or contract example2's address?

Answer 1

Then is C() will print contract example1's address or contract example2's address?

It will print example1's address. When this code :

function B() {
    print msg.sender; 
    C();   }

will be executed, VM will read it like this:

function B() {
        print msg.sender;
        print msg.sender; // code of C()
}

That's why, it will print example1's address.