2nd/10_Wiki/Dev/Topic_C/C_Constants.md

id, title, category, status, verification_status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, created_at, updated_at, review_reason, merge_history, tags, raw_sources, applied_in, github_commit

id	title	category	status	verification_status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	created_at	updated_at	review_reason	merge_history	tags	raw_sources	applied_in	github_commit
c-constants	C Constants	Programming_Language	draft	conceptual		const keyword read-only variables C 상수		B	0.85	2026-07-04	2026-07-04			c programming-language w3schools constants	https://www.w3schools.com/c/c_constants.php

C Constants

🎯 한 줄 통찰 (One-line insight)

A const variable MUST be assigned a value at the moment of declaration — declaring it first and assigning later (const int minutesPerHour; minutesPerHour = 60;) is explicitly shown as an error — meaning const isn't just "can't change later," it also removes the two-step declare-then-assign pattern that ordinary variables freely support. [S1]

🧠 핵심 개념 (Core concepts)

• const keyword — makes a variable unchangeable/read-only after its initial assignment. [S1]
• Mandatory initialization — a const variable must receive its value at declaration time; assigning it afterward is a compile error. [S1]
• Uppercase naming convention — while not required, C programmers commonly write constant names in uppercase (e.g. BIRTHYEAR) for readability. [S1]
• Use case — values unlikely to ever change during program execution (e.g. minutesPerHour, monthsInYear). [S1]

📖 세부 내용 (Details)

• Attempting reassignment fails: const int myNum = 15; myNum = 10; // error: assignment of read-only variable 'myNum'. [S1]
• Declare-without-assign fails: const int minutesPerHour; minutesPerHour = 60; // error. [S1]
• Uppercase convention: const int BIRTHYEAR = 1980;. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• const는 선언과 동시에 초기화 필수: 일반 변수처럼 먼저 선언만 하고 나중에 값을 대입하는 방식이 const에서는 컴파일 에러를 발생시킨다는 점이 명시적으로 확인됨. [S1]

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — 시간당 분(60), 연중 개월 수(12)처럼 절대 변하지 않는 값을 const로 선언하는 것이 실전 코드에서의 표준 활용이다. [S1]

💻 코드 패턴 (Code patterns)

Declaring constants that must be initialized at the point of declaration (C):

const int minutesPerHour = 60;
const int monthsInYear = 12;
const int BIRTHYEAR = 1980;  // uppercase is a common naming convention

✅ 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 Data Types RealLife, C Storage Classes
• 참조 맥락: 상수 선언 — 저장 클래스(Storage Classes) 챕터로 이어짐.

📚 출처 (Sources)

• [S1] W3Schools — C Constants — https://www.w3schools.com/c/c_constants.php

📝 변경 이력 (Change history)

• 2026-07-04: Initial draft synthesized from the W3Schools "C Constants" page (Astra wiki-curation, P-Reinforce v3.1 format).