2nd/10_Wiki/Dev/Topic_Java/Java_Arrays_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
java-arrays-loop	Java Arrays Loop	Programming_Language	draft	conceptual		자바 배열 순회		B	0.9	2026-07-04	2026-07-04			java programming w3schools arrays loops	https://www.w3schools.com/java/java_arrays_loop.asp

Java Arrays Loop

🎯 한 줄 통찰 (One-line insight)

The choice between a regular for loop and for-each over an array comes down to whether you need the index — for-each only gives values, so tasks needing both position and value (like labeling theater seats) require the regular indexed for loop instead. [S1]

🧠 핵심 개념 (Core concepts)

• Regular for with .length — for (int i = 0; i < cars.length; i++) iterates by index. [S1]
• For-each (: read as "in") — for (String car : cars) iterates values without an index. [S1]
• Sum accumulation — sum += numbers[i] inside an indexed loop. [S1]
• Trade-off — for-each is simpler/more readable but gives no access to the index; use regular for when index is needed. [S1]

🧩 추출된 패턴 (Extracted patterns)

• Index-needed rule of thumb — the source gives a concrete deciding example: printing seat numbers requires BOTH the index (seat number) and the value (occupant name), so a regular for loop is the correct choice there, not for-each. [S1]

📖 세부 내용 (Details)

• Indexed print: String[] cars = {"Volvo", "BMW", "Ford", "Mazda"}; for (int i = 0; i < cars.length; i++) { System.out.println(cars[i]); }. [S1]
• Sum: int[] numbers = {1, 5, 10, 25}; int sum = 0; for (int i = 0; i < numbers.length; i++) { sum += numbers[i]; } System.out.println("The sum is: " + sum);. [S1]
• For-each: for (String car : cars) { System.out.println(car); }. [S1]
• Index needed (seats): String[] seats = {"Jenny", "Liam", "Angie", "Bo"}; for (int i = 0; i < seats.length; i++) { System.out.println("Seat number " + i + " is taken by " + seats[i]); }. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• for-each의 한계: 값만 제공하고 인덱스는 제공하지 않으므로, 인덱스가 필요한 경우 일반 for 루프를 써야 한다는 점이 명시됨. [S1]

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — 좌석 번호 출력처럼 인덱스+값이 모두 필요한 경우가 일반 for 루프 선택의 기준이 된다. [S1]

💻 코드 패턴 (Code patterns)

Sum via indexed loop (Java):

int[] numbers = {1, 5, 10, 25};
int sum = 0;
for (int i = 0; i < numbers.length; i++) {
    sum += numbers[i];
}
System.out.println("The sum is: " + sum);

✅ 검증 상태 및 신뢰도

• 상태: draft
• 검증 단계: conceptual
• 출처 신뢰도: B (W3Schools — widely used educational reference, not a primary standards body)
• 신뢰 점수: 0.90
• 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

• 상위/루트: Java Tutorial
• 관련 개념: Java Arrays, Java For Each Loop, Java Arrays Real Life
• 참조 맥락: 배열 순회의 두 가지 방법 — 인덱스 필요 여부가 선택 기준.

📚 출처 (Sources)

• [S1] W3Schools — Java Arrays Loop — https://www.w3schools.com/java/java_arrays_loop.asp

📝 변경 이력 (Change history)

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