Unit 9 Animation and Games in Javascript (CodeHS)

Front

Which of the following statements are true about the code in the image: I. ball is a local variable II. the ball variable in draw is different from the ball variable in main III. ball is a global variable IV. ball’s scope includes both main and draw

Back

III. and IV.

Front

The following program animates a ball using a timer. We want the animation to stop when the user clicks the mouse. Which statement would stop the animation in this program?

Back

Front

What goes in the blank?

Back

Front

Which of the following Does Not make code more reusable?
- Using const variables instead of hard-coded values
- Using specific values in functions instead of using parameters
- Writing multiple functions that solve small subproblems rather than one function which solves the entire problem
- Using parameters to generalize functions

Back

Using specific values in functions instead of using parameters

Front

Which function is more reusable?

Back

Front

Imagine you are filling a 100 by 100 canvas with circles. They are touching but not overlapping at four points. Their radius is 10. How many circles will fit on the canvas?

Back

25

Front

What statement would you use to determine if ball is hitting the right edge of the window?

Back

Front

On the circle named ball, what are the coordinates of point A?

Back

Front

Imagine we have a canvas with two graphics objects, a circle named ball, and a square named box. How can you determine if ball’s left edge is hitting box?

Back

Front

In the following code what would you need to add to line 51 and line 56 to make sure the ball bounces off the right and left edges of the window and reverses its direction?

Back

1. dx = -dx;