The goal of this problem set is to practice writing simple functions. The functions consume atomic forms of data (numbers, symbols, images). Some use conditionals to distinguish among different situations.

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HtDP Problems

4.2.1, 4.4.1, 4.4.4, 5.1.2

Problem A1

Formulate the formulas from Problems 2 and 3 on Set 1 as Scheme programs. Then apply the strategy of HtDP problem 4.2.4 to formulate automatic tests for these three programs (using check-expect instead of =). Make sure to turn at least two examples from your table into tests.

Problem A2

Find an image of a spaceship on the web. Then develop a program that "flies" the spaceship on a 200 x 500 canvas from bottom to top. When the ship's top end reaches the top margin, make the ship re-appear on the bottom.

Your program should clearly identify at what speed the spaceship moves and a single change to your program should change the speed of the ship.