---
id: c-comments
title: "C Comments"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["single-line comments", "multi-line comments", "C 주석"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.85
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["c", "programming-language", "w3schools", "comments"]
raw_sources: ["https://www.w3schools.com/c/c_comments.php"]
applied_in: []
github_commit: ""
---

# [[C Comments]]

## 🎯 한 줄 통찰 (One-line insight)
Before C99 (1999), single-line `//` comments were NOT part of standard C at all — only `/* */` multi-line comments existed — meaning `//` comments, now the default choice for short notes, are actually a relatively recent addition to the language's ~50-year history, not an original feature. [S1]

## 🧠 핵심 개념 (Core concepts)
- **Single-line comments (`//`)** — everything from `//` to the end of the line is ignored by the compiler. [S1]
- **Multi-line comments (`/* */`)** — everything between the markers is ignored, regardless of line count. [S1]
- **Comments as code-disabling tool** — `//` can be prefixed to a line of working code to temporarily disable it during testing, without deleting it. [S1]
- **Historical constraint** — pre-C99, only `/* */` was valid; `//` support was added in the C99 standard. [S1]

## 📖 세부 내용 (Details)
- Single-line comment before code: `// This is a comment` followed by `printf("Hello World!");`. [S1]
- Single-line comment disabling code: `printf("This will run"); // printf("This will NOT run");`. [S1]
- Multi-line comment: `/* The code below will print the words Hello World! to the screen, and it is amazing */ printf("Hello World!");`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **// 주석의 표준화 시점**: C99(1999) 이전에는 다중 줄 주석(/* */)만 사용 가능했고, 한 줄 주석(//)은 C99부터 표준에 포함되었다는 역사적 사실이 명시됨 — 구형 컴파일러/표준 준수 코드 작성 시 유의해야 할 사항. [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 특정 코드 줄을 지우지 않고 // 로 임시 비활성화하는 것이 실전 디버깅/테스트에서 흔히 쓰이는 기법이다. [S1]

## 💻 코드 패턴 (Code patterns)
Temporarily disabling a line of code using a single-line comment instead of deleting it (C):
```c
printf("This will run");
// printf("This will NOT run");
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.85
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[C Tutorial]]
- **관련 개념:** [[C Output]], [[C Organize Code]]
- **참조 맥락:** 주석 문법 — 코드 조직화(Organize Code) 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — C Comments — https://www.w3schools.com/c/c_comments.php

## 📝 변경 이력 (Change history)
- 2026-07-04: Initial draft synthesized from the W3Schools "C Comments" page (Astra wiki-curation, P-Reinforce v3.1 format).