2nd/10_Wiki/Topics/Domain_Programming/Topic_Java/Java_Numbers.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
java-numbers	Java Numbers	Programming_Language	draft	conceptual		byte short int long float double 자바 숫자 타입		B	0.9	2026-07-04	2026-07-04			java programming w3schools numbers int double	https://www.w3schools.com/java/java_data_types_numbers.asp

Java Numbers

🎯 한 줄 통찰 (One-line insight)

long values need a trailing L and float values need a trailing f (double needs d, but it's optional since double is the default) — omitting these suffixes on large/decimal literals causes compile errors or silent precision loss. [S1]

🧠 핵심 개념 (Core concepts)

• Integer types — byte, short, int (preferred default for whole numbers), long (for values too large for int, requires L suffix). [S1]
• Floating point types — float (requires f suffix, 6-7 decimal digit precision), double (15-16 digit precision, preferred for most calculations). [S1]
• Scientific notation — float f1 = 35e3f; double d1 = 12E4d; uses e/E for powers of 10. [S1]

🧩 추출된 패턴 (Extracted patterns)

• Literal suffix requirement scales with type size — L for long, f for float, d for double (optional) — the suffix tells the compiler which literal type to use, since Java's default numeric literal types are int and double. [S1]
• double as the safe default for decimals — the tutorial explicitly recommends double over float for most calculations due to its much higher precision. [S1]

📖 세부 내용 (Details)

• byte: byte myNum = 100; (range -128 to 127). [S1]
• short: short myNum = 5000; (range -32768 to 32767). [S1]
• int: int myNum = 100000; (preferred default). [S1]
• long: long myNum = 15000000000L; (note the L suffix). [S1]
• float: float myNum = 5.75f;. [S1]
• double: double myNum = 19.99d;. [S1]
• Scientific notation: float f1 = 35e3f; double d1 = 12E4d;. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

소스에서 모순되는 정보는 발견되지 않음.

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — Type Casting 챕터에서 이 숫자 타입들 간 자동/수동 변환이 다뤄진다. [S1]

💻 코드 패턴 (Code patterns)

Long and float literal suffixes (Java):

long myNum = 15000000000L;
float myFloat = 5.75f;
double myDouble = 19.99d;  // d is optional (double is the default)

✅ 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 Data Types, Java Type Casting, Java Math
• 참조 맥락: 6개 숫자 타입의 상세 — 리터럴 접미사(L/f/d) 규칙이 핵심.

📚 출처 (Sources)

• [S1] W3Schools — Java Numbers — https://www.w3schools.com/java/java_data_types_numbers.asp

📝 변경 이력 (Change history)

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