Test — Module 1: Types and Variables¶

Topic: [[go]] Module: [[go/1. Types and Variables]]

Before You Begin¶

[!WARNING] Do not look at ANSWERS.md or your notes during the test. The purpose of this test is to surface what you truly know vs. what you think you know. An inflated score is worthless. An honest score shows you exactly where to focus next.

Instructions: 1. Close all notes, the module README, and any reference materials. 2. Set a timer. Note your start time below. 3. Attempt every question — partial credit exists. 4. After finishing, grade yourself using ANSWERS.md. 5. Record your score in the Grading Record at the bottom.

Start time: ___________ End time: ___________ Total time: ___________

Scoring Table¶

Passing score: 15/22 (68%)  ·  Target score: 18/22 (82%)

Section 1: Recall (5 questions × 1 pt = 5 pts)¶

Quick recall questions. Answer from memory in 1–3 sentences each.

1.1 What is the zero value of an int in Go? What is the zero value of a string? What is the zero value of a pointer?

Your answer:

1.2 What does the := operator do, and where can it be used? Where is it not allowed?

Your answer:

1.3 Name three integer types available in Go besides int.

Your answer:

1.4 What does iota represent in a Go constant block? What value does it start at, and when does it reset?

Your answer:

1.5 What is the difference between byte and rune in Go? What underlying types are they aliases for?

Your answer:

Section 2: Conceptual Understanding (3 questions × 2 pts = 6 pts)¶

Demonstrate that you understand the "why", not just the "what".

2.1 Explain why Go requires explicit type conversion between numeric types and what class of bugs this prevents. Give a specific example of a bug that implicit conversion could cause.

Your answer:

2.2 A colleague says: "Go's zero values are wasteful because you always have to initialize variables anyway — you end up writing count := 0 instead of just count :=, so zero values don't save you any work."

Is this claim correct? If not, what is the accurate understanding, and under what circumstances do zero values genuinely save effort?

Your answer:

2.3 Compare Go's type system to Python's. What are the tradeoffs of each approach? Under what circumstances would Go's static typing be a significant advantage? Under what circumstances might Python's dynamic typing be preferable?

Your answer:

Section 3: Applied / Practical (2 questions × 3 pts = 6 pts)¶

Show that you can use your knowledge to solve real problems.

3.1 Write a complete, runnable Go program that declares a const block using iota to represent the four cardinal directions (North = 0, East = 1, South = 2, West = 3) and prints each one with its numeric value.

Requirements: - Use a const block with iota - Print all four directions with their values in the format North: 0 - The program must compile (use correct package main, import "fmt", and func main())

Your answer:

3.2 Write a complete, runnable Go program that converts temperatures. Take three hardcoded Celsius values (0.0, 37.0, 100.0), convert each to Fahrenheit using the formula F = C * 9/5 + 32, and print both with exactly 2 decimal places using fmt.Printf("%.2f°C = %.2f°F\n", c, f).

Requirements: - Use float64 for all temperature variables - Use the correct formula (beware integer division) - Output must match the format: 0.00°C = 32.00°F

Your answer:

Section 4: Scenario / Debugging (1 question × 3 pts = 3 pts)¶

Analyze a realistic scenario and identify what's wrong or what should be done.

4.1 The following code is supposed to print the string "65" but prints "A" instead:

package main

import "fmt"

func main() {
    n := 65
    fmt.Println(string(n))
}

Identify:

a) What is wrong?

b) Why does this happen? Explain the underlying mechanism.

c) How would you fix it? Write the corrected code.

Your answer:

Section 5: Essay / Discussion (1 question × 2 pts = 2 pts)¶

Open-ended. There is more than one good answer. Show your reasoning.

5.1 Go has no implicit type conversion between numeric types. Some developers find this verbose and frustrating — for example, you cannot add an int and a float64 without an explicit cast. Others consider it one of Go's best features. Argue for or against this design decision with at least two specific examples. Justify your conclusion based on what you've learned in this module.

Consider at least two perspectives in your answer.

Your answer (aim for 3–6 sentences):

Section 6: Bonus Challenge (1 question × +5 pts)¶

[!NOTE] This question is optional. It will not count against you if you skip it or get it wrong. Only attempt it after completing Sections 1–5.

6.1 Go's integer types (int8, int16, int32, int64, uint8, etc.) have fixed sizes, but int and uint are platform-dependent (32-bit on 32-bit systems, 64-bit on 64-bit systems).

Explain when you would choose int vs. int64 in production code. Your answer should specifically address: - What risks arise from choosing int for values that may be stored, serialized, or sent over a network - What risks arise from choosing int64 for general-purpose counters and indices - How the choice interacts with Go's encoding/json package and other serialization formats - What the Go standard library itself does (for example, what type does len() return, and why?)

This may require combining knowledge from this module with independent reasoning beyond the module content.

Your answer:

Self-Assessment¶

After grading your test, answer these questions honestly:

What did I get right and why?

Your reflection:

What did I get wrong and why did I make that mistake?

Your reflection:

What should I review before moving to the next module?

Your reflection:

What score did I get? Do I feel it accurately reflects my understanding?

Your reflection:

Grading Record¶

Append a new row each time you take this test. Do not overwrite previous attempts.

Grade scale: A ≥ 90% (≥20/22)  ·  B ≥ 80% (≥18/22)  ·  C ≥ 70% (≥15/22)  ·  D ≥ 60% (≥13/22)  ·  F < 60%

See ANSWERS.md for the answer key. Review it only after completing the test.