2nd/10_Wiki/Topic_Programming/Topic_CPP/CPP_Function_Reference.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-function-reference	C++ Functions - Pass By Reference	Programming_Language	draft	conceptual		pass by reference swap function C++ 참조로 전달		B	0.87	2026-07-04	2026-07-04			cpp programming-language w3schools functions references	https://www.w3schools.com/cpp/cpp_function_reference.asp

CPP Functions - Pass By Reference

🎯 한 줄 통찰 (One-line insight)

Passing a parameter as int &num lets a function PERMANENTLY change the caller's actual variable using ordinary assignment syntax (num = 50;) with no * dereference needed anywhere — a much simpler syntax than C's equivalent (which requires passing &myCar and using -> inside the function) — showing that C++'s reference feature does the SAME job as C's pointer-parameter pattern but eliminates every pointer-specific symbol from both the call site and the function body. [S1]

🧠 핵심 개념 (Core concepts)

• type &param — a reference parameter; the function receives an ALIAS to the caller's actual variable, not a copy. [S1]
• No dereference syntax needed — unlike a pointer parameter, using num directly (no *num) reads or writes the caller's original variable. [S1]
• Swap pattern — void swapNums(int &x, int &y) can swap the CALLER's two variables permanently, since both parameters are aliases to the originals. [S1]
• Works for any type, including string — void modifyStr(string &str) mutates the caller's original string. [S1]

📖 세부 내용 (Details)

• Changing a caller's variable through a reference parameter: void changeValue(int &num) { num = 50; } int value = 10; changeValue(value); cout << value; // 50. [S1]
• Swapping two caller variables: void swapNums(int &x, int &y) { int z = x; x = y; y = z; } swapNums(firstNum, secondNum); // firstNum and secondNum are now swapped. [S1]
• Mutating a string through a reference: void modifyStr(string &str) { str += " World!"; } string greeting = "Hello"; modifyStr(greeting); cout << greeting; // "Hello World!". [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• 참조 전달은 포인터 전달보다 문법이 훨씬 간단함: C에서는 &myCar로 넘기고 함수 안에서 ->로 접근해야 했지만, C++의 참조 매개변수는 & 없이 num처럼 직접 써서 원본 값을 바꿀 수 있다는 점에서 동일한 기능을 훨씬 단순한 문법으로 제공함이 확인됨. [S1]

🛠️ 적용 사례 (Applied in summary)

두 정수 변수의 값을 서로 맞바꾸는 swapNums() 함수가 참조 전달의 대표적인 실전 활용 사례로 원문에 직접 제시됨. [S1]

💻 코드 패턴 (Code patterns)

Swapping two of the caller's variables using reference parameters (C++):

void swapNums(int &x, int &y) {
  int z = x;
  x = y;
  y = z;
}
int main() {
  int firstNum = 10;
  int secondNum = 20;
  swapNums(firstNum, secondNum); // both are permanently swapped
  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 Function Array, CPP Function Structures, CPP References
• 참조 맥락: 참조로 전달 — 구조체를 함수로 전달(Function Structures) 챕터로 이어짐.

📚 출처 (Sources)

• [S1] W3Schools — C++ Functions - Pass By Reference — https://www.w3schools.com/cpp/cpp_function_reference.asp

📝 변경 이력 (Change history)

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