2nd/10_Wiki/Dev/Topic_C/C_Operators_Arithmetic.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
c-operators-arithmetic	C Arithmetic Operators	Programming_Language	draft	conceptual		integer division increment decrement C 산술 연산자		B	0.86	2026-07-04	2026-07-04			c programming-language w3schools operators arithmetic	https://www.w3schools.com/c/c_operators_arithmetic.php

C Arithmetic Operators

🎯 한 줄 통찰 (One-line insight)

Dividing two int values ALWAYS produces an int result, silently truncating any decimal — 10 / 3 gives 3, not 3.33 — and the ONLY way to get a decimal result is to make at least the operand types float/double (10.0 / 3 gives 3.333...), meaning integer division isn't a rounding behavior to configure, it's an unavoidable consequence of the operand types chosen. [S1]

🧠 핵심 개념 (Core concepts)

• Seven core arithmetic operators — + (add), - (subtract), * (multiply), / (divide), % (modulus/remainder), ++ (increment), -- (decrement). [S1]
• Integer division truncation — dividing two ints always yields an int, discarding any decimal remainder; use float/double operands to get a decimal result. [S1]
• Increment/decrement round-trip — incrementing then decrementing the same variable (or vice versa) returns it to its original value. [S1]

📖 세부 내용 (Details)

• All seven operators demonstrated together: int x = 10; int y = 3; x + y; // 13, x - y; // 7, x * y; // 30, x / y; // 3, x % y; // 1, plus ++z/--z on a separate variable. [S1]
• Integer vs decimal division contrast: int a = 10; int b = 3; printf("%d\n", a / b); // 3 (integer division) versus double c = 10.0; double d = 3.0; printf("%f\n", c / d); // 3.333.... [S1]
• Real-life counting example: int peopleInRoom = 0; peopleInRoom++; peopleInRoom++; peopleInRoom++; // 3 people enter, count = 3 then peopleInRoom--; // 1 leaves, count = 2. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• 정수 나눗셈의 소수점 절삭: int끼리 나누면 항상 int 결과가 나와 소수점이 버려진다는 점이 명시되며, 소수 결과를 원하면 최소 한쪽을 float/double로 만들어야 한다는 해결책이 함께 제시됨. [S1]

🛠️ 적용 사례 (Applied in summary)

방에 들어오고 나가는 사람 수를 ++/--로 세는 카운터 예제가 원문에서 직접 실전 활용 사례로 제시됨. [S1]

💻 코드 패턴 (Code patterns)

Integer division truncates; use float/double operands for a decimal result (C):

int a = 10;
int b = 3;
printf("%d\n", a / b); // Integer division, result is 3

double c = 10.0;
double d = 3.0;
printf("%f\n", c / d); // Decimal division, result is 3.333...

✅ 검증 상태 및 신뢰도

• 상태: draft
• 검증 단계: conceptual
• 출처 신뢰도: B (W3Schools — widely used educational reference, not a primary standards body)
• 신뢰 점수: 0.86
• 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

• 상위/루트: C Tutorial
• 관련 개념: C Operators, C Operators Assignment
• 참조 맥락: 산술 연산자 — 대입 연산자(Operators Assignment) 챕터로 이어짐.

📚 출처 (Sources)

• [S1] W3Schools — C Arithmetic Operators — https://www.w3schools.com/c/c_operators_arithmetic.php

📝 변경 이력 (Change history)

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