I.6 Semester I Review 6
Random numbers. Gas gauge. Graphing in people coordinates.
What does it do?
Write check-expects.
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Write two check-expects for the
double-circle-img
function (abbeviatedci
):(define (double-circle-image img) (image-width (beside (circle 40 "solid" "blue") img (circle 40 "solid" "blue"))))
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Write and test a function
r2d
that returns a random two digit number. There is a 40% chance of the number beginning with a 2 and a 60% chance of it beginning with a 1. The ones digit should be random. -
Gas gauge. You are making a text based gas gauge function.
gas-gauge: number -> string
- The readout result will be 16 X’s when the tank is full, and then should O’s
for the part that is empty. For example, half full is
"XXXXXXXXOOOOOOOO"
. - The gas tank can hold a maximum of 12 gallons.
- When the tank is over half full, round number of X’s, so 96% reads full.
- When the tank is less than half full, always round down (floor) the number of X’s to avoid suddenly running out of gas. (So 6% reads empty.)
- The readout result will be 16 X’s when the tank is full, and then should O’s
for the part that is empty. For example, half full is
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Graphing. You are making an animation where a red circle follows the people-coordinate graph of the function
y = 1/600 * (x-200) * (x+200)
- Graphing window is 500x300.
- Both x and y axes are visible.
- People-coordinate origin is (250,150) in computer coordinates.
- Positive y-axis for the graph is up.
- As you move the mouse, the red point shows on the graph is directly above/below your mouse.