2nd/10_Wiki/Dev/Topic_C/C_While_Loop.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-while-loop	C While Loop	Programming_Language	draft	conceptual		while statement zero-iteration loop C while 반복문		B	0.86	2026-07-04	2026-07-04			c programming-language w3schools loops while	https://www.w3schools.com/c/c_while_loop.php

C While Loop

🎯 한 줄 통찰 (One-line insight)

A while loop can run ZERO times — if its condition is already false the very first time it's checked (e.g. int i = 10; while (i < 5) {...}), the body never executes at all, not even once — a behavior the source explicitly contrasts against the upcoming do/while chapter, which guarantees at least one execution regardless of the initial condition. [S1]

🧠 핵심 개념 (Core concepts)

• while (condition) { ... } — repeats the block as long as the condition remains true, checked BEFORE each iteration (including the first). [S1]
• Zero-iteration possibility — if the condition is false from the start, the loop body never runs at all. [S1]
• Mandatory condition-variable update — forgetting to change the loop-controlling variable inside the body (e.g. omitting i++) causes an infinite loop. [S1]
• i as a counter convention — the source explains i is traditionally used because it's short and stands for "index"/"iterator," not an arbitrary choice. [S1]

📖 세부 내용 (Details)

• Basic counting loop: int i = 0; while (i < 5) { printf("%d\n", i); i++; }. [S1]
• Countdown loop: int countdown = 3; while (countdown > 0) { printf("%d\n", countdown); countdown--; } printf("Happy New Year!!\n");. [S1]
• Zero-iteration case: int i = 10; while (i < 5) { printf("This will never be printed\n"); i++; } — body never executes since the condition is false immediately. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• 조건이 처음부터 거짓이면 while 루프는 한 번도 실행 안 됨: do/while 루프(다음 챕터)와 달리 일반 while 루프는 시작부터 조건이 거짓이면 본문이 단 한 번도 실행되지 않는다는 점이 명시적으로 대비됨. [S1]

🛠️ 적용 사례 (Applied in summary)

카운트다운 후 "Happy New Year!!"를 출력하는 예제가 원문에서 직접 실전 활용 사례로 제시됨. [S1]

💻 코드 패턴 (Code patterns)

A while loop that never executes because its condition is false from the start (C):

int i = 10;
while (i < 5) {
  printf("This will never be printed\n");
  i++;
}

✅ 검증 상태 및 신뢰도

• 상태: draft
• 검증 단계: conceptual
• 출처 신뢰도: B (W3Schools — widely used educational reference, not a primary standards body)
• 신뢰 점수: 0.86
• 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

• 상위/루트: C Tutorial
• 관련 개념: C Switch, C While Loop RealLife, C Do While Loop
• 참조 맥락: 반복문 섹션 첫 챕터 — while 루프 실전 예제(While Loop RealLife) 챕터로 이어짐.

📚 출처 (Sources)

• [S1] W3Schools — C While Loop — https://www.w3schools.com/c/c_while_loop.php

📝 변경 이력 (Change history)

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