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70 lines
3.1 KiB
Markdown
70 lines
3.1 KiB
Markdown
---
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id: c-math
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title: "C Math Functions"
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category: "Programming_Language"
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status: "draft"
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verification_status: "conceptual"
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canonical_id: ""
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aliases: ["math.h", "sqrt ceil floor pow", "C 수학 함수"]
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duplicate_of: ""
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source_trust_level: "B"
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confidence_score: 0.83
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created_at: 2026-07-04
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updated_at: 2026-07-04
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review_reason: ""
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merge_history: []
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tags: ["c", "programming-language", "w3schools", "math", "math.h"]
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raw_sources: ["https://www.w3schools.com/c/c_math.php"]
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applied_in: []
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github_commit: ""
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---
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# [[C Math Functions]]
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## 🎯 한 줄 통찰 (One-line insight)
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`ceil()` and `floor()` both return a `float`/`double`, NOT an `int` — printing `ceil(1.4)` with `%f` still shows a decimal-formatted result (`2.000000`), meaning "rounding" in C's math library doesn't convert the value to an integer type; it just replaces the fractional part while preserving the floating-point representation, so further formatting or casting is still the caller's job. [S1]
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## 🧠 핵심 개념 (Core concepts)
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- **`<math.h>`** — required header for math functions beyond basic arithmetic operators. [S1]
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- **`sqrt(x)`** — returns the square root of `x`. [S1]
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- **`ceil(x)`** — rounds UP to the nearest integer value (still returned as a float/double). [S1]
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- **`floor(x)`** — rounds DOWN to the nearest integer value (still returned as a float/double). [S1]
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- **`pow(x, y)`** — returns x raised to the power of y (xʸ). [S1]
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## 📖 세부 내용 (Details)
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- Square root: `printf("%f", sqrt(16));`. [S1]
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- Rounding up vs down on the same value: `printf("%f", ceil(1.4)); printf("%f", floor(1.4));` — ceil gives 2.000000, floor gives 1.000000. [S1]
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- Exponentiation: `printf("%f", pow(4, 3));` — 4³ = 64. [S1]
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## ⚖️ 모순 및 업데이트 (Contradictions & updates)
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- 현재까지 발견된 모순 사항 없음 (No contradictions found in available sources).
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## 🛠️ 적용 사례 (Applied in summary)
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현재 발견된 실제 적용 사례가 없습니다 — sqrt/ceil/floor/pow는 게임 로직이나 그래픽 계산 등에서 흔히 결합해 쓰이는 기본 수학 함수 집합이다. [S1]
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## 💻 코드 패턴 (Code patterns)
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Rounding up and down, both still returned as floating-point values (C):
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```c
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#include <math.h>
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printf("%f", ceil(1.4)); // 2.000000
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printf("%f", floor(1.4)); // 1.000000
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```
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## ✅ 검증 상태 및 신뢰도
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- **상태:** draft
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- **검증 단계:** conceptual
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- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
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- **신뢰 점수:** 0.83
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- **중복 검사 결과:** 신규 생성 (New discovery)
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## 🔗 지식 그래프 (Knowledge Graph)
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- **상위/루트:** [[C Tutorial]]
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- **관련 개념:** [[C Strings Functions]], [[C Random Numbers]]
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- **참조 맥락:** 수학 함수 — 난수 생성(Random Numbers) 챕터로 이어짐.
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## 📚 출처 (Sources)
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- [S1] W3Schools — C Math Functions — https://www.w3schools.com/c/c_math.php
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## 📝 변경 이력 (Change history)
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- 2026-07-04: Initial draft synthesized from the W3Schools "C Math Functions" page (Astra wiki-curation, P-Reinforce v3.1 format).
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