2nd/10_Wiki/Topics/Topic_Programming/Topic_CPP/CPP_Scope.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-scope	C++ Variable Scope	Programming_Language	draft	conceptual		local scope global scope shadowing C++ 변수 스코프		B	0.85	2026-07-04	2026-07-04			cpp programming-language w3schools scope	https://www.w3schools.com/cpp/cpp_scope.asp

CPP Variable Scope

🎯 한 줄 통찰 (One-line insight)

This chapter, and its exact example (a local x=22 shadowing a global x=5), is IDENTICAL to C's Variable Scope chapter — confirming that C++'s scope rules, including the silent-shadowing behavior where same-named local and global variables coexist as two independent variables with no error, are inherited from C completely unmodified. [S1]

🧠 핵심 개념 (Core concepts)

• Scope — the region where a variable is accessible; local (inside a function) or global (outside any function). [S1]
• Local scope — a variable created inside a function only usable within it; error if accessed outside. [S1]
• Global scope — accessible from ANY scope, both other functions and main(). [S1]
• Name collision = shadowing, not conflict — a local variable with the SAME NAME as a global one creates two independent variables; the local one takes precedence inside its function. [S1]
• Global mutability risk — any function can silently modify a global, making state harder to reason about. [S1]

📖 세부 내용 (Details)

• Same-name shadowing — two independent variables coexist: int x = 5; void myFunction() { int x = 22; cout << x; // 22, local } int main() { myFunction(); cout << x; // 5, global — untouched }. [S1]
• A function silently mutating a global: int x = 5; void myFunction() { cout << ++x; } // x is now 6. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• 현재까지 발견된 모순 사항 없음 (No contradictions found in available sources). C 챕터와 완전히 동일한 스코프 규칙(섀도잉, 전역 변수 위험성)이 확인됨.

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — 기존 C++ 프로그램이나 협업 코드에서 전역 변수를 마주칠 가능성이 높으므로 스코프 동작 원리를 이해해두는 것이 실전에서 유용하다고 원문에 명시됨. [S1]

💻 코드 패턴 (Code patterns)

A local variable shadowing a global variable of the same name (C++):

int x = 5; // global
void myFunction() {
  int x = 22; // local, shadows the global
  cout << x << "\n"; // 22 (local x)
}
int main() {
  myFunction();
  cout << x; // 5 (global x, untouched)
  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: 0.85
• 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

• 상위/루트: C++ Tutorial
• 관련 개념: CPP Namespaces, CPP User Input, C Scope
• 참조 맥락: 변수 스코프 — 사용자 입력(User Input) 챕터로 이어짐.

📚 출처 (Sources)

• [S1] W3Schools — C++ Variable Scope — https://www.w3schools.com/cpp/cpp_scope.asp

📝 변경 이력 (Change history)

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