DSA · Theory

Implementation of Stack using Array

Theory

17/810

Don’t start Implementation of Stack using Array with jargon. Start with undo typing. That is the whole point.

Implementation of Stack using Array on the board: push / pop LIFO. Then say what undo typing looks like after.

Without Implementation of Stack using Array, a tiny editor gets messy and undo typing is hard to trust.

Implementation of Stack using Array shows up in a tiny editor. Name undo typing, not “a real-world scenario”.

If undo typing breaks under Implementation of Stack using Array, check pop on empty first.

Place Implementation of Stack using Array next to nearby DSA work — push / pop LIFO is the link.

One breath for Implementation of Stack using Array, then undo typing, then pop on empty. Sit down.

Diagram

    | 3 |  ← top (pop)
    | 2 |
    | 1 |
    LIFO

Exam tip

For Implementation of Stack using Array: definition + a tiny editor + one failure.

stack = []
stack.append(10)   # push
stack.append(20)
print(stack.pop()) # 20
print(stack[-1])   # peek → 10

Implementation of Stack using Array — stack is LIFO: push/pop from the same end.

DefImplementation of Stack using Array — Neha uses it for undo typing in a tiny editor.
RuleImplementation of Stack using Array → push / pop LIFO.
RememberImplementation of Stack using Array + a dry-run table (a tiny editor).
UseImplementation of Stack using Array in a tiny editor (undo typing).
TrapImplementation of Stack using Array — pop on empty.
ExImplementation of Stack using Array → undo typing.