[SOLVED] CS220 Lab#9 -High Level Language

Name: Date:

The Jack Programming Language

Standard Class Library

1. Translate the following Java code into its equivalent Jack code.

3. Write the Jack code that produces the following transaction with the user.Note: the green text indicates input from the user.

4. Write the Jack code that produces the following transaction with the user.Note: the green text indicates input from the user.

5. Translate the entire Main class (written in Java) into its Jack equivalent.

6. Convert the following Java class (Fraction.java) into its Jack equivalent (two files/classes named Fraction.jack and Main.jack).

7. Write a Jack program that will display a square (30 pixels x 30 pixels), starting in the top-left (x=0, y=0) of the screen, then moving around the edge of the screen clockwise (e.g. along the top edge, then right edge, bottom edge, left edge) until it gets back to the origin.

The square should move by itself, with a short wait between each movement.

Summative Questions:

8. When we execute a Jack program, the first subroutine that starts running is:main()
9. Can a subroutine in one Jack class access field variables of another Jack class?

No, unless you create getter methods.

10. Which Jack classes should have a method for disposing objects?

All Jack classes should provide this.

11. What does the keyword this implicitly refer to? (Select all that apply)
12. In constructors: the current object
13. In functions: the current object
14. In methods: the current object
15. In Main.main: the current object

12. Which of the following are true about Jack classes? (Select all that apply)
13. A Jack class must have a constructor
14. A Jack class can contain either methods, or functions, but not both
15. Each Jack class must be stored in a separate file
16. Each Jack class must have a subroutine named main