Stack Applications

Postfix Expression Evaluation

Post-fix Expressions
- Order: left-operand, right-operand, operator.
- Parentheses are never needed.
- Example: 3 4 + 5 6 + *.
Evaluation
- Begin with an empty stack.
- Process the tokens from left to right.
- If the token is a number,
  - Push it onto the stack.
- If the token is a binary operator,
  - Pop two numbers off the stack.
  - Combine them under the operator.
  - Push the result onto the stack.
- The expression value is the single remaining value on the stack.
Example - PostfixEvaluator.cpp, arraystack.h, arraylist.h.

This page was last modified on Mar 28, 2001

URL: http://people.hsc.edu/faculty-staff/robbk/Coms262/Lectures/StackAppsPostfix.html