The stack
A stack is nothing more than a piece of contiguous memory.
This is important to know. A computer only has memory, it doesn’t have a special stack memory and a heap memory; it’s all part of the same memory.
The difference is how this memory is accessed and used. The stack supports simple push/pop instructions on a contiguous part of memory, that’s what makes it fast to use. The heap memory is allocated by a memory allocator on demand and can be scattered around in different locations.
We’ll not go through the differences between the stack and the heap here since there are numerous articles explaining them in detail, including a chapter in The Rust Programming Language at https://doc.rust-lang.org/stable/book/ch04-01-what-is-ownership.html#the-stack-and-the-heap.
What does the stack look like?
Let’s start with a simplified view of the stack. A 64-bit CPU will read 8 bytes at a time. Even though the natural way for us to see...
