CS201 - Spring 2014 - Class 6
- Move office hours tomorrow: 1:30-3pm
- Lab tutors
- public: accessible outside of the class
- static: stand-alone method that does not access/require any state of an object (i.e. access instance variables)
- void: doesn't return anything
- main: name of the method
- String: an array of Strings
- args: the name of the parameter
- A package is a collection of classes
- often related
- Any class inside a particular package my use any other class in the package without doing anything special
- If you want to use a class that is not inside your package, you need to import it
- To import a class:
- For example:
- imports the Random class from the java.util package
- imports the Scanner class from the java.util package
Design a stopwatch class
- What functionality should we have?
- Be specific about the functionality:
- What happens if we call start twice in a row?
- What happens if we call stop twice in a row? or without having called start?
- What happens if we call start then call reset (without calling stop)?
- What data do we need to store?
- start time
- stop time (or accumulated time)
- whether it's running or not (what happens if we just hit stop twice without using a running variable?)
- what happens if we press start twice before pressing stop?
- noop (nothing happens, just keeps running)
we'd like to change a few things about the current stopwatch class
- add methods to get the elapsed time in seconds, minutes and hours (rounded down)
- change the functionality of the start method so as to reset the start time if you press start when the watch is already timing
what's the best way to do this?