2nd/10_Wiki/Topic_Programming/Topic_CPP/CPP_Access_Specifiers.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-access-specifiers	C++ Access Specifiers	Programming_Language	draft	conceptual		public private protected default is private C++ 접근 지정자		B	0.87	2026-07-04	2026-07-04			cpp programming-language w3schools oop access-specifiers	https://www.w3schools.com/cpp/cpp_access_specifiers.asp

CPP Access Specifiers

🎯 한 줄 통찰 (One-line insight)

If a class member is declared with NO access specifier at all, it defaults to private — the exact behavior the earlier Classes chapter's public: requirement was silently protecting against — meaning every class example up to this point that used public: was actively OVERRIDING C++'s default visibility, not merely adding an optional label; omitting it entirely would have made those attributes inaccessible from outside. [S1]

🧠 핵심 개념 (Core concepts)

• Three access specifiers — public (accessible from outside the class), private (NOT accessible from outside), protected (not accessible from outside, but accessible in INHERITED/child classes). [S1]
• Default access is private — a class with no explicit access specifier makes ALL its members private automatically. [S1]
• Private-by-default as good practice — declaring attributes private "as often as you can" reduces the chance of accidental misuse; this is the core ingredient of Encapsulation (next chapter). [S1]
• Real-life analogy — public = front door (anyone can enter); private = locked drawer (only the owner); protected = family-only room (children/subclasses can enter, others cannot). [S1]

📖 세부 내용 (Details)

• Mixed public/private members and the resulting access error: class MyClass { public: int x; private: int y; }; MyClass myObj; myObj.x = 25; // Allowed myObj.y = 50; // error: y is private. [S1]
• Default-private class with no explicit specifier: class MyClass { int x; int y; }; // both x and y are private by default. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• 접근 지정자 생략 시 기본값은 private: 이전 Classes 챕터에서 사용된 public:이 단순한 선택적 표시가 아니라, 생략 시 기본으로 적용되는 private를 의도적으로 override한 것이었음이 이 챕터에서 명확히 확인됨. [S1]

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — 클래스 속성을 가능한 한 private으로 선언하는 것이 실전 코드에서 좋은 관행으로 권장되며, 이는 다음 챕터(Encapsulation)의 핵심 재료가 된다. [S1]

💻 코드 패턴 (Code patterns)

Mixed public and private members, with the resulting compile error on private access (C++):

class MyClass {
public:    // Public access specifier
  int x;   // Public attribute
private:   // Private access specifier
  int y;   // Private attribute
};
int main() {
  MyClass myObj;
  myObj.x = 25;  // Allowed (public)
  myObj.y = 50;  // error: y is private
  return 0;
}

✅ 검증 상태 및 신뢰도

• 상태: draft
• 검증 단계: conceptual
• 출처 신뢰도: B (W3Schools — widely used educational reference, not a primary standards body)
• 신뢰 점수: 0.87
• 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

• 상위/루트: C++ Tutorial
• 관련 개념: CPP Constructors Overloading, CPP Encapsulation, CPP Inheritance Access
• 참조 맥락: 접근 지정자 — 캡슐화(Encapsulation) 챕터로 이어짐, protected는 상속 접근(Inheritance Access) 챕터와 직접 연결.

📚 출처 (Sources)

• [S1] W3Schools — C++ Access Specifiers — https://www.w3schools.com/cpp/cpp_access_specifiers.asp

📝 변경 이력 (Change history)

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