Sample Quiz Questions

• Answer each in one or two sentences:
  • Why is it a good idea to encapsulate values like Colors as classes?
  • In our BankAccount example, we used Java exceptions to rule out the possibility of overdrawing an account. Another way to do this would be to define the methods to just not do anything at all if asked to withdraw more money than was held. Why is using exceptions a better way to do this?
  • How can you draw a 10X10 red square in the upper left corner within an Applet's `paint' method? (Describe or show code.)
• Write the full contents of the file Blender.Java that defines a class Blender that provides a simple model (without any graphical representation or other extensions) of a blender that can either be OFF, or running at LO or HI speed, where lo speed means that it is running at 100RPM and hi speed means 500RPM. (Note that you can translate these basic ideas into instance variables and methods in several ways. Pick something that makes sense to you, explaining in comments anything that you think need explanation.)
• Given this class describing linked nodes, where each node holds a number:

        public class LinkedNumber {
          protected int number_ = 0;
          protected LinkedNumber next_ = null;
  
          /** create new node with indicated value and successor **/        
          public LinkedNumber(int initialValue, LinkedNumber n) {
            number_ = initialValue;
            next_ = n;
          }
  
          /** return currently held number */
          public int value() { return number_; }
        
          public void incrementAll() {
            // write me
        }
        

  Write method incrementAll, that increments the value held by all nodes in the list.