---
id: c-syntax
title: "C Syntax"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["main function", "include stdio", "C 문법"]
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", "syntax"]
raw_sources: ["https://www.w3schools.com/c/c_syntax.php"]
applied_in: []
github_commit: ""
---

# [[C Syntax]]

## 🎯 한 줄 통찰 (One-line insight)
The compiler is explicitly indifferent to whitespace and line breaks — the source shows the ENTIRE `main()` body collapsible onto a single line (`int main(){printf("Hello World!");return 0;}`) and produces identical behavior — meaning C's multi-line formatting convention exists purely for human readability, not because the language requires it, unlike languages where indentation/newlines are syntactically meaningful. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`#include <stdio.h>`** — includes a header enabling input/output functions like `printf()`; described as something that "almost always appears" in a C program. [S1]
- **`main()`** — the special function where program execution begins; code inside its `{}` is what actually runs. [S1]
- **Statement termination** — every C statement must end with a semicolon `;`. [S1]
- **`return 0`** — ends `main()` and sends a value back to the operating system; `0` conventionally signals "everything worked." [S1]
- **Whitespace insignificance** — blank lines and extra spaces are ignored by the compiler; used only to aid human readability. [S1]

## 📖 세부 내용 (Details)
- Standard multi-line form: `#include <stdio.h> int main() { printf("Hello World!"); return 0; }`. [S1]
- Equivalent single-line form (compiler behaves identically): `int main(){printf("Hello World!");return 0;}`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **줄바꿈/공백은 순전히 가독성 목적**: 컴파일러가 여러 줄로 쓰인 코드와 한 줄로 압축한 코드를 동일하게 처리한다는 점이 직접적인 코드 비교로 증명됨. [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 이 챕터의 문장 단위 분해 설명이 이후 모든 C 코드를 읽는 기초 독해 능력의 토대가 된다. [S1]

## 💻 코드 패턴 (Code patterns)
The canonical C program structure, annotated line by line:
```c
#include <stdio.h>

int main() {
  printf("Hello World!");
  return 0;
}
```

## ✅ 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 Get Started]], [[C Statements]]
- **참조 맥락:** C 프로그램 구조 설명 — 명령문(Statements) 챕터로 이어짐.

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

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