---
id: csharp-variables-constants
title: "C# Constants"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["const keyword C#", "C# 상수"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.84
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["csharp", "programming-language", "w3schools", "constants"]
raw_sources: ["https://www.w3schools.com/cs/cs_variables_constants.php"]
applied_in: []
github_commit: ""
---

# [[CSharp Constants]]

## 🎯 한 줄 통찰 (One-line insight)
C#'s `const` keyword is placed BEFORE the type (`const int myNum = 15;`), exactly mirroring C's `const int` and C++'s identical placement — but C# adds a strictness neither predecessor enforces at the same chapter level: a `const` MUST be initialized at declaration, with no separate "declare now, assign later" escape hatch, producing a hard compiler error ("A const field requires a value to be provided") rather than the vaguer undefined/uninitialized-value risk C's const-without-init could silently create. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`const` keyword** — placed before the variable type, makes the variable unchangeable and read-only after its initial assignment. [S1]
- **Mandatory initialization** — a `const` MUST be assigned a value at the point of declaration; declaring one without a value is a compile error. [S1]
- **Use case** — values that should never change, like PI (3.14159...), protecting code from accidental overwrites by the same or other developers. [S1]

## 📖 세부 내용 (Details)
- Declaration + illegal reassignment: `const int myNum = 15; myNum = 20; // error`. [S1]
- Explicit error message quoted from the compiler: "A const field requires a value to be provided" when a const is declared without a value. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **초기화 없는 const 선언이 하드 에러로 즉시 차단됨**: C의 `const int x;`는 선언 자체는 허용되고 이후 대입이 불가능해 초기화되지 않은 값이 남는 위험이 있었지만, C#은 초기화 없는 const 선언 자체를 컴파일 에러로 명시적으로 차단한다는 점이 이번 챕터에서 확인됨. [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — PI처럼 절대 변하지 않아야 하는 값의 예시로 const 사용이 원문에서 언급됨. [S1]

## 💻 코드 패턴 (Code patterns)
const requires initialization at declaration — no exceptions (C#):
```csharp
const int myNum = 15;
myNum = 20; // error - cannot assign to a const variable
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.84
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[C# Tutorial]]
- **관련 개념:** [[CSharp Variables Identifiers]], [[CSharp Variables Display]], [[C Constants]]
- **참조 맥락:** Variables 섹션 — Display Variables 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — C# Constants — https://www.w3schools.com/cs/cs_variables_constants.php

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