Quiz 3 Solution

Why do we use pseudo-code to document an algorithm, rather than a natural language like English or a programming language like Python?

Pseudo-code is more precise than natural language, and yet easier for beginners to understand than a programming language.

Carefully trace the following algorithm. What does it output? Be sure to mark a section of your answer as the output, separate from your scratch work.

1. Let N be 8
2. Set I to 1
3. If I > N then stop.
4. If I < 4 or I is odd, then output I
5. Set I to I+1
6. Go back to step 3.

Tracing pseudo-code from Christopher League on Vimeo.

Give an example of each kind of pseudo-code instruction. Refer to the relevant step numbers in the algorithm above.

1. Input: Something like “Let N be a positive integer” (where the user can choose which integer).
2. Output: A statement that says “output” or “print”, like step 4.
3. Variable assignment: A statements that says “Set name to value”, like steps 2 or 5.
4. Conditional: A statement using an “if”, like steps 3 or 4.
5. Loop: A statement that repeats previous steps, like step 6 above.