Question: How many bytes is `unsigned long long`?
Is it the same as `unsigned long long int` ?

Answer: 
The beauty of C++, like C, is that the sized of these things are implementation-defined, so there's no correct answer without your specifying the compiler you're using. Are those two the same? Yes. "long long" is a synonym for "long long int", for any compiler that will accept both.
Use the operator `sizeof`, it will give you the size of a type expressed in byte. One byte is eight bits. See the following program:

```
#include <iostream>

int main(int,char**)
{
 std::cout << "unsigned long long " << sizeof(unsigned long long) << "\n";
 std::cout << "unsigned long long int " << sizeof(unsigned long long int) << "\n";
 return 0;
}

```