Software Development: Problem Solving, Design, Testing and the Life Cycle: Unit Review

Undo in reverse: 26 + 4 = 30, then 30 ÷ 3 = 10. Check: 10 × 3 − 4 = 26 ✓.

8. 2⁷ = 128 is less than 200, but 2⁸ = 256 is at least 200.

Trial and error (brute-force search). It is reasonable when the number of possibilities is small enough for the computer to check quickly.

Input: three distances. Processing: total = d1 + d2 + d3; average = total ÷ 3. Output: total and average, labelled with km.

Tax = 80 × 0.13 = 10.40; total = $90.40.

A value calculated during processing and then used again. In the road-trip program, litres is used to calculate the cost.

The driver types and focuses on the current line; the navigator reviews each line and thinks about the overall plan. They swap often.

The formula takes a few operations for any n (more efficient). The loop takes n additions but is easier to change (for example to add only even numbers).

Example: "I expected Total: 13 for the inputs 5, 8, 0, but I get Total: 5. I checked the input lines; the loop seems to run only once, so I think I wrote if where I needed while." (Expected, actual, what was tried.)

Decision: diamond. Input: parallelogram. Calculation: rectangle. Start: terminator (rounded oval).

n: 2 → 5 → 11 → 23 → 47. 47 is not < 30, so the output is 47.

for i in range(3, 7): (range stops before its end value).

A return value.

Data can only enter or leave a store through a process, which checks and changes it.

Name: Rink. Attributes: - name: str, - capacity: int. Methods: + is_full(people: int): bool.

A placeholder function with the right name and parameters that returns a simple value. It lets the skeleton run (and be tested) before every function is written.

High cohesion: each module does one job. Low coupling: modules communicate only through parameters and return values, not shared globals.

import tools and print(tools.double(21)). Output: 42.

Example: input("Number of guests (1-20): ").

It says what went wrong, how to fix it, and is polite.

if checks only once; while keeps asking until the input is valid.

math.sqrt(9 * 9 + 12 * 12) = √225 = 15.0.

Up to 12 (12 × 12 = 144 ≤ 150, 13 × 13 = 169 > 150). 150 is not prime: the very first divisor tried, 2, divides it.

A = π × 4 × 4 = 16π ≈ 50.3 cm².

Append 7; 14 > 7 shifts; 9 > 7 shifts; 6 < 7 stops. Result [2, 6, 7, 9, 14], with 2 shifts.

Found at index 1; 15 and 20 shift left; the last slot is removed. Returns True, list [5, 15, 20].

Any three: empty list; insert a new smallest or largest value; insert a duplicate; delete the only item; delete a value that is not there.

ValueError, ZeroDivisionError, IndexError, ValueError.

B. "4.5" is not a valid int, so the except block runs.

d = 16 − 40 = −24 < 0, so none: it returns [] without calling math.sqrt.

Problem definition, analysis, design, writing code, testing, implementation, maintenance.

Milestone: "specification approved by the client on (date)". Product: the specification.

Example: "The daily report lists each homeroom on its own line, sorted from most to fewest coats, with the total on the last line."

A: 0-3; B: 3-5; C: 3-7; D: 7-8. Length 8 days, critical path A → C → D, B's slack 2 days.

(2 + 12 + 10) ÷ 6 = 24 ÷ 6 = 4.0 days.

Milestones; work completed; work in progress and outstanding; issues and risks; next steps.

Boundary: 49 → fail, 50 → pass (also 0 and 100 are valid boundaries). Invalid: −1 and 101 (or "fifty") → rejected with a message.

So the program's output cannot influence what you accept as correct.

Black-box chooses tests from the specification only; white-box looks at the code and makes sure every branch and loop runs.

k = 1: t = 1; k = 2: t = 2; k = 3: t = 6. Prints 6.

A temporary, clearly labelled print that shows variable values while the program runs. Remove it once the bug is fixed.

Any list of all-positive numbers, such as [4, 9, 7]: it returns 0 instead of 4. Fix: start with smallest = values[0].

room = room.strip().upper() in add_donation().

Record a change request, estimate its effect on time and milestones, agree with the client, and usually schedule it for the next version.

The installed program and the user guide (plus the handover and demonstration).