7. Exercises 6

Opener

A digital thermometer gives temperature readouts with one decimal place. The random-therm function gives a possible temperature reading between $96.7$ and $100.5$, inclusive. Write the random-therm function.

Random

• (ball-jump) A ball is supposed to teleport around the screen, moving to a random x coordinate. The x-coordinates chosen should be multiples of 10 between 70 and 250. Write a function that will give the new x-coordinate. Example of random choices:

    (ball-jump 0) => 90
    (ball-jump 0) => 170
    (ball-jump 0) => 120
  

Distances

• (dist-to-circ) A circle has radius $80$ and center $(200,150)$. Write a function to compute the distance from $(x,y)$ to the circle. When $(x,y)$ is inside the circle or on the perimeter of the circle, the distance is $0$.

• (dist-to-sq) Harder Challenge. A square of side length 50 is placed with center at (175,90). Find the distance from a point (x,y) to the square. If your point is inside the square, the distance is zero. Draw a picture.

Other

• (swerve-heading) A compass is currently pointing a certain direction between 0 and 359 degrees. (0 degrees = North, not that it matters) The driver swerves a little bit, changing the heading by a random amount, at most ten degrees in either direction. The swerve-heading function takes in the original direction and produces the new, randomly varied, direction.

  Once you have the basic method working, make sure that the output direction is between 0 and 359 degrees. When the current heading is near 0 or 360 it can be a little tricky.