docs(10_Wiki): 위키 구조 정리 — 언어 튜토리얼 카테고리 폴더 제거 + 신규 자산 동기화

Topic_CSS/Topic_HTML/Topic_JavaScript/Topic_Prompt/Topic_Comfyui 등 기존 카테고리 폴더를 정리하고, Topic_Graphic/Dev 등 신규 산출물과 Topics 내부 세션/메모리 기록을 동기화.
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+---
+id: java-operators-arithmetic
+title: "Java Operators Arithmetic"
+category: "Programming_Language"
+status: "draft"
+verification_status: "conceptual"
+canonical_id: ""
+aliases: ["increment decrement", "자바 산술 연산자"]
+duplicate_of: ""
+source_trust_level: "B"
+confidence_score: 0.9
+created_at: 2026-07-04
+updated_at: 2026-07-04
+review_reason: ""
+merge_history: []
+tags: ["java", "programming", "w3schools", "operators", "arithmetic", "increment"]
+raw_sources: ["https://www.w3schools.com/java/java_operators_arithmetic.asp"]
+applied_in: []
+github_commit: ""
+---
+
+# [[Java Operators Arithmetic]]
+
+## 🎯 한 줄 통찰 (One-line insight)
+Dividing two `int` values ALWAYS truncates to an integer result (`10 / 3` gives `3`, not `3.33`) — getting a decimal result requires both operands to be `double`, making this a common source of silent precision loss for beginners. [S1]
+
+## 🧠 핵심 개념 (Core concepts)
+- **Arithmetic operators** — `+`, `-`, `*`, `/`, `%` (modulus), `++` (increment), `--` (decrement). [S1]
+- **Integer division truncates** — `int / int` always yields an `int`, discarding any remainder. [S1]
+- **Double division preserves decimals** — `double / double` yields the actual fractional result. [S1]
+- **`++`/`--`** — increase/decrease a variable by exactly 1. [S1]
+- **Increment then decrement cancels out** — ending value equals the starting value. [S1]
+
+## 🧩 추출된 패턴 (Extracted patterns)
+- **Integer division truncation is the classic footgun** — `10 / 3` silently gives `3` in Java (as in most statically-typed languages), unlike Python 3 where `/` always returns a float; this difference trips up developers moving between languages. [S1]
+- **Counter pattern via ++/--** — tracking a running count (e.g. people entering/leaving a room) is the canonical real-world use of increment/decrement. [S1]
+
+## 📖 세부 내용 (Details)
+- All operators demoed: `int x = 10; int y = 3; println(x + y); println(x - y); println(x * y); println(x / y); println(x % y);`. [S1]
+- Integer vs. double division: `int a = 10; int b = 3; System.out.println(a / b); // 3 (truncated)` vs. `double c = 10.0d; double d = 3.0d; System.out.println(c / d); // 3.333...`. [S1]
+- Increment/decrement counter: `int peopleInRoom = 0; peopleInRoom++; peopleInRoom++; peopleInRoom--;`. [S1]
+
+## ⚖️ 모순 및 업데이트 (Contradictions & updates)
+- **정수 나눗셈의 절삭 동작**: `int / int`는 항상 정수 결과를 반환하며 소수점 이하는 버려진다는 점이 명시적으로 경고됨 — Type Casting 챕터의 double 캐스팅 해법과 연결된다. [S1]
+
+## 🛠️ 적용 사례 (Applied in summary)
+현재 발견된 실제 적용 사례가 없습니다 — 사람 수 카운팅 같은 실전 예제에서 증감 연산자의 용도가 직접 등장한다. [S1]
+
+## 💻 코드 패턴 (Code patterns)
+Integer division truncates, double division doesn't (Java):
+```java
+int a = 10, b = 3;
+System.out.println(a / b);  // 3 (truncated)
+
+double c = 10.0d, d = 3.0d;
+System.out.println(c / d);  // 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:** 0.90
+- **중복 검사 결과:** 신규 생성 (New discovery)
+
+## 🔗 지식 그래프 (Knowledge Graph)
+- **상위/루트:** [[Java Tutorial]]
+- **관련 개념:** [[Java Operators]], [[Java Type Casting]], [[Java Numbers]]
+- **참조 맥락:** 정수 나눗셈 절삭 문제는 Type Casting 챕터의 double 캐스팅 해법과 직접 연결된다.
+
+## 📚 출처 (Sources)
+- [S1] W3Schools — Java Arithmetic Operators — https://www.w3schools.com/java/java_operators_arithmetic.asp
+
+## 📝 변경 이력 (Change history)
+- 2026-07-04: Initial draft synthesized from the W3Schools "Java Arithmetic Operators" page (Astra wiki-curation, P-Reinforce v3.1 format).