---
id: csharp-strings
title: "C# Strings"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: [".Length property", "ToUpper ToLower", "C# 문자열"]
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", "strings"]
raw_sources: ["https://www.w3schools.com/cs/cs_strings.php"]
applied_in: []
github_commit: ""
---

# [[CSharp Strings]]

## 🎯 한 줄 통찰 (One-line insight)
C# exposes string length as a PROPERTY (`txt.Length`, no parentheses) rather than a METHOD call, which is a subtle but real divergence from both C++'s `std::string::length()` (a method call with parens) and Java's `.length()` (also a method call) — the tutorial's own example (`txt.Length`) reveals that C# treats a string "as an object" but distinguishes properties (state you read) from methods (behavior you invoke, like `.ToUpper()`), a distinction C++/Java collapse into "just call a method for everything." [S1]

## 🧠 핵심 개념 (Core concepts)
- **String = object with properties and methods** — unlike C's raw char arrays, a C# string is genuinely an object. [S1]
- **`.Length` property** — no parentheses; accessed like a field, not called like a function (`txt.Length`, NOT `txt.Length()`). [S1]
- **`.ToUpper()` / `.ToLower()`** — methods (with parentheses) that return a NEW string converted to upper/lower case, leaving the original unchanged. [S1]

## 📖 세부 내용 (Details)
- Basic declaration: `string greeting = "Hello";` / multi-word: `string greeting2 = "Nice to meet you!";`. [S1]
- Length: `string txt = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; Console.WriteLine("The length of the txt string is: " + txt.Length);` → 26. [S1]
- Case conversion: `string txt = "Hello World"; Console.WriteLine(txt.ToUpper()); Console.WriteLine(txt.ToLower());`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **Length가 메서드가 아니라 프로퍼티임**: C++의 `std::string::length()`와 Java의 `.length()`는 둘 다 괄호를 붙여 호출하는 메서드였지만, C#의 `.Length`는 괄호 없이 필드처럼 접근하는 프로퍼티라는 점이 확인됨 — C#은 "상태를 읽는 것(프로퍼티)"과 "동작을 호출하는 것(메서드, 예: `.ToUpper()`)"을 문법적으로 구분함. [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 문자열 길이 출력과 대소문자 변환 예제가 원문에서 제시됨. [S1]

## 💻 코드 패턴 (Code patterns)
Property access (no parens) vs. method call (with parens) on a string (C#):
```csharp
string txt = "Hello World";
Console.WriteLine(txt.Length);     // property -- no parentheses -> 11
Console.WriteLine(txt.ToUpper());  // method -- parentheses -> "HELLO WORLD"
Console.WriteLine(txt.ToLower());  // method -- parentheses -> "hello world"
```

## ✅ 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 Strings Concat]], [[CPP Strings]], [[Java Strings]]
- **참조 맥락:** Strings 섹션 — String Concatenation 챕터로 이어짐.

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

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