2nd/10_Wiki/Dev/Topic_CPP/CPP_Functions_Recursion.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
cpp-functions-recursion	C++ Recursion	Programming_Language	draft	conceptual		recursive function base case factorial recursion C++ 재귀		B	0.85	2026-07-04	2026-07-04			cpp programming-language w3schools functions recursion	https://www.w3schools.com/cpp/cpp_functions_recursion.asp

CPP Recursion

🎯 한 줄 통찰 (One-line insight)

The exact same three examples (range-sum via sum(k), countdown, factorial) with the exact same step-by-step unfolding explanation reappear here verbatim from C's Recursion chapter — confirming C++'s recursion semantics, base-case requirement, and termination risks are inherited from C completely unmodified. [S1]

🧠 핵심 개념 (Core concepts)

• Recursion — a function calling ITSELF, breaking a complex problem into smaller instances of the same problem. [S1]
• Base case — the condition under which the function stops calling itself (k > 0 becoming false), essential for termination. [S1]
• Unwinding accumulation — each recursive call combines its own contribution with the result of the smaller sub-call. [S1]
• Risk of non-termination or excess resource use — without a solid base case, recursion can run forever or exhaust memory/processor time. [S1]

📖 세부 내용 (Details)

• Summing 1 to 10 via recursion: int sum(int k) { if (k > 0) { return k + sum(k - 1); } else { return 0; } } — unfolds as 10 + (9 + (8 + ... + sum(0))). [S1]
• Countdown via recursion: void countdown(int n) { if (n > 0) { cout << n << " "; countdown(n - 1); } }. [S1]
• Factorial via recursion: int factorial(int n) { if (n > 1) { return n * factorial(n - 1); } else { return 1; } } — factorial(5) = 120. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• 현재까지 발견된 모순 사항 없음 (No contradictions found in available sources). C 챕터와 완전히 동일한 재귀 예제와 설명이 확인됨.

🛠️ 적용 사례 (Applied in summary)

5의 팩토리얼(5×4×3×2×1=120)을 재귀로 계산하는 예제가 원문에서 직접 실전 활용 사례로 제시됨. [S1]

💻 코드 패턴 (Code patterns)

A recursive function with a clear base case that guarantees termination (C++):

int factorial(int n) {
  if (n > 1) {
    return n * factorial(n - 1);
  } else {
    return 1; // base case
  }
}

✅ 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: CPP Function Structures, CPP Functions Lambda, C Functions Recursion
• 참조 맥락: 재귀 — 람다 함수(Functions Lambda) 챕터로 이어짐.

📚 출처 (Sources)

• [S1] W3Schools — C++ Recursion — https://www.w3schools.com/cpp/cpp_functions_recursion.asp

📝 변경 이력 (Change history)

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