---
id: c-arrays
title: "C Arrays"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["array declaration", "fixed-size array", "C 배열"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.86
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["c", "programming-language", "w3schools", "arrays"]
raw_sources: ["https://www.w3schools.com/c/c_arrays.php"]
applied_in: []
github_commit: ""
---

# [[C Arrays]]

## 🎯 한 줄 통찰 (One-line insight)
Mixing types in an array literal (`int myArray[] = {25, 50, 75, 3.15, 5.99};`) doesn't always fail loudly — the source shows the float values `3.15`/`5.99` get silently TRUNCATED to `3`/`5` (since the array is typed `int`), and only "in some cases" does it produce an error, meaning the type-mismatch guard here is a silent-data-loss trap more often than a hard compile failure. [S1]

## 🧠 핵심 개념 (Core concepts)
- **Array literal creation** — `type name[] = {val1, val2, ...};` creates and initializes an array in one step. [S1]
- **Zero-based indexing** — `[0]` is the first element, `[1]` the second, and so on. [S1]
- **Mutable elements** — any element can be reassigned by index after creation (`myNumbers[0] = 33;`). [S1]
- **Size-first declaration** — `int myNumbers[4];` reserves space for 4 elements to be filled in later; the SIZE CANNOT CHANGE after creation. [S1]
- **Same-type requirement** — all elements must share one data type; mismatched types get silently truncated/converted, not cleanly rejected. [S1]

## 📖 세부 내용 (Details)
- Literal array creation and access: `int myNumbers[] = {25, 50, 75, 100}; printf("%d", myNumbers[0]); // 25`. [S1]
- Modifying an element by index: `myNumbers[0] = 33; // Now outputs 33 instead of 25`. [S1]
- Size-first, fill-later declaration: `int myNumbers[4]; myNumbers[0] = 25; myNumbers[1] = 50; myNumbers[2] = 75; myNumbers[3] = 100;`. [S1]
- Type-mismatch truncation trap: `int myArray[] = {25, 50, 75, 3.15, 5.99};` — 3.15 and 5.99 silently become 3 and 5. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **타입이 섞이면 조용히 잘림**: int 배열에 float 값을 넣으면 항상 에러가 나는 게 아니라 대부분 소수점이 잘려나가는 형태로 조용히 처리되며, 일부 경우에만 에러가 발생한다는 점이 명시적으로 경고됨. [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 크기를 먼저 선언하고 나중에 요소를 채우는 방식이 데이터가 순차적으로 들어올 때(예: 사용자 입력 반복) 실전에서 활용된다. [S1]

## 💻 코드 패턴 (Code patterns)
Declaring an array's size first, then filling in elements later (C):
```c
int myNumbers[4];
myNumbers[0] = 25;
myNumbers[1] = 50;
myNumbers[2] = 75;
myNumbers[3] = 100;
```

## ✅ 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 Break Continue]], [[C Arrays Size]]
- **참조 맥락:** 배열 섹션 첫 챕터 — 배열 크기(Arrays Size) 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — C Arrays — https://www.w3schools.com/c/c_arrays.php

## 📝 변경 이력 (Change history)
- 2026-07-04: Initial draft synthesized from the W3Schools "C Arrays" page (Astra wiki-curation, P-Reinforce v3.1 format).
