Picture a pile of dishes: push places a new element on top, so it becomes the first element available to remove. This is the stack’s insertion operation under the LIFO policy. section 8.3 section 8.19
A push operation follows a small set of practical rules:
- Adds only at the top of the stack; arbitrary insertion is not part of the stack interface. section 8.3
- Makes the new element the next candidate for pop, preserving last-in, first-out order. section 8.19
- Can validate values before insertion, such as rejecting an empty string in a string stack. section 8.10
def push(self, value):
self._data.insert_in_front(value)
A linked-list-backed stack can implement push by forwarding insertion to the list’s front, reusing tested storage logic. section 8.10
