The list of directories ACTS like a stack — you push a directory onto the top of the stack, and pop a directory off the top again to get it back.
该目录列表的行为就像一个堆栈——您将一个目录压入堆栈顶部，并从顶部弹出一个目录以取回它。
2
If a function is executing, then the stack pointer is pointing to the top of the whole stack, which is also the top of that function's activation record.
如果一个函数正在执行，那么堆栈指针就会指向整个堆栈的顶部，这也是该函数活动记录的顶部。
3
These steps are typically handled through continuous communications that stack key messages on top of one another.