KTUYSBeta
Log inSign up

Cheat sheet · Class 12 · CBSE · Science Computer Science

Stack cheat sheet

The whole chapter on one page: key formulas, facts and the points to remember, for quick revision before a test.

CBSE Class 12 · Computer Science

Cheat sheet

Chapter 5Stack

LIFO — Last In, First Out (a pile of plates).

1. Operations

  • PUSH: add to top (list.append).
  • POP: remove from top (list.pop()).
  • PEEK/TOP: view top.
  • isEmpty; overflow and underflow.

2. Applications

  • Undo in editors; browser back button.
  • Reversing a string.
  • Matching parentheses.
  • Evaluating and converting expressions.
NotationExample
InfixA + B * C
Prefix (Polish)
  • A * B C
Postfix (reverse Polish)A B C * +

3. Postfix Evaluation

Scan left to right: push operands; on an operator pop two, apply, push the result. 2 3 4 * + → 14

4. Key Points

  • Underflow: pop from an empty stack.
  • Infix → postfix uses operator precedence.
  • Function calls use a call stack.
  • Python list works as a stack.

Remember: LIFO | push/pop | infix, prefix, postfix

Stack: questions and notes

More Class 12 · CBSE · Science Computer Science cheat sheets

Practise Stack

Sign up free to practise the full chapter. Questions you get wrong come back until you've mastered them.

Start practising free

Free to start · No credit card needed