Questions — Module 1: Types and Variables¶

Log questions as they arise — don't wait until you understand them fully. A question written down is a learning opportunity captured. For big-picture questions about the whole topic, use the topic-level QUESTIONS.md instead.

How to Use This File¶

1. Write the question the moment it occurs to you, even if you can't articulate it well yet.
2. Come back and refine the question once you understand it better.
3. Update the status as you research or find answers.
4. Link to the source where you found the answer.
5. Capture follow-up questions — good answers always raise new ones.

Status Legend¶

Question Format¶

### Q{{N}}: {{SHORT_QUESTION_TITLE}}

**Asked:** {{YYYY-MM-DD}}
**Status:** 🔴 Unanswered

**Full question:**
The complete question with all relevant context.

**My current hypothesis:**
What you think the answer might be, even if speculative.

**Answer:**
_To be filled in_

**Source / Confirmed by:**
_Where you found or verified the answer_

**Follow-up questions:**
- _New questions this answer raised_

Questions¶

Q001: When should I choose int vs int64?¶

Asked: YYYY-MM-DD Status: 🔴 Unanswered

Full question: The module explains that int is platform-dependent (32-bit on 32-bit systems, 64-bit on 64-bit systems), while int64 is always 64-bit. In practice, most servers are 64-bit, so int and int64 are usually the same size. When does this distinction actually matter in production code?

My current hypothesis: I think int64 matters when writing data to disk or sending it over a network — where the byte layout must be consistent regardless of where the code runs. But for in-memory loop counters and array indices, int is probably fine.

Answer: To be filled in

Source / Confirmed by: To be filled in — check go.dev/ref/spec and "The Go Programming Language" book

Follow-up questions: - What does the Go standard library itself use — int or int64 for lengths and indices?

Q002: Can I do arithmetic between int and float64 directly?¶

Asked: YYYY-MM-DD Status: 🔴 Unanswered

Full question: Go requires explicit type conversion. So var x int = 5; var y float64 = 3.14; z := x + y should fail to compile. But what exactly does the error message say, and what is the canonical fix?

My current hypothesis: The compiler error is something like "mismatched types int and float64". The fix is z := float64(x) + y, converting x to float64 before the addition.

Answer: To be filled in

Source / Confirmed by: Test in the Go playground at go.dev/play

Follow-up questions: - Are there any cases where Go does implicit numeric conversion (perhaps with untyped constants)?

Q003: What exactly happens with iota if you skip lines in a const block?¶

Asked: YYYY-MM-DD Status: 🔴 Unanswered

Full question: iota increments for each constant in a block. But what if I use a blank identifier _ to skip a value? Does iota still increment?

My current hypothesis: I believe _ in a const block does consume an iota value, because _ is still a constant specification — it just discards the name. So:

const (
    _ = iota  // 0, discarded
    A         // 1
    B         // 2
)

Answer: To be filled in

Source / Confirmed by: To be filled in — test in go.dev/play

Follow-up questions: - Is this pattern (_ = iota to skip 0) ever used in real Go code?

Q004: Does Go's zero-value guarantee apply to struct fields?¶

Asked: YYYY-MM-DD Status: ⏸ Deferred

Full question: The module explains zero values for primitive types. But if I declare a struct variable without initializing it, do all its fields also get their zero values? This seems like it should be true, but I want to confirm.

My current hypothesis: Yes — when you declare var s MyStruct, every field of s is initialized to its type's zero value. This is part of Go's "no garbage" guarantee. A struct's zero value is the struct with all fields zeroed.

Answer: To be filled in

Source / Confirmed by: To be answered in the Structs module — deferring until then

Follow-up questions: - Can a struct be "usefully zero-valued" (work correctly without explicit initialization)? Is this a design pattern in Go?

Add new questions below this line. Keep them numbered sequentially.

Resolved Questions Archive¶

Move fully answered 🟢 questions here to keep the active list clean.

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Question Stats¶