Four Function Calculator
This is a supplemental task description for HW02, where we practice basic in-browser JS, HTML, and CSS.
Here's an old 4-function calculator:
Relevent features:
- A display showing a single number.
- A grid of 4 by 4 buttons including:
- Numbers 0 - 9
- Four arithmetic operators (with + also acting as =).
- C means "clear"
- Decimal point
The calculator can be modeled as a state machine. Pressing any button does something meaningful at any time, but number buttons do two different things depending on the state:
- Sometimes they add a digit to the current number.
- Sometimes they start a new number.
Pressing a button should call a JavaScript function that updates the internal state and the display as appropriate.