---
id: csharp-classes-multi
title: "C# Multiple Classes and Objects"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["multiple objects same class C#", "separate files classes C#", "C# 다중 클래스"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.82
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["csharp", "programming-language", "w3schools", "oop", "classes"]
raw_sources: ["https://www.w3schools.com/cs/cs_classes_multi.php"]
applied_in: []
github_commit: ""
---

# [[CSharp Multiple Classes and Objects]]

## 🎯 한 줄 통찰 (One-line insight)
This short chapter is largely a distilled repeat of patterns already shown in Class Members (multiple objects of one class, splitting fields/methods into one class and `Main()` into another) — its only genuinely new emphasis is calling out the `public` keyword by its formal name, "access modifier," and stating outright that without it, a field defined in one class (`Car`) would NOT be reachable from another class (`Program`), making the two-file `prog2.cs`/`prog.cs` split only work BECAUSE of that modifier. [S1]

## 🧠 핵심 개념 (Core concepts)
- **Multiple objects of one class** — `Car myObj1 = new Car(); Car myObj2 = new Car();` — each is an independent instance. [S1]
- **Splitting classes across files** — one class (fields/methods) in one file (`prog2.cs`), another class (with `Main()`) in a separate file (`prog.cs`) — recommended for organization. [S1]
- **`public` = access modifier** — explicitly named as such here; it's what makes a field defined in `Car` reachable from the unrelated `Program` class. Without `public`, cross-class access would fail. [S1]

## 📖 세부 내용 (Details)
- Two objects, same class: `class Car { string color = "red"; static void Main(string[] args) { Car myObj1 = new Car(); Car myObj2 = new Car(); Console.WriteLine(myObj1.color); Console.WriteLine(myObj2.color); } }`. [S1]
- Cross-file class + access: `prog2.cs`: `class Car { public string color = "red"; }`; `prog.cs`: `class Program { static void Main(string[] args) { Car myObj = new Car(); Console.WriteLine(myObj.color); } }`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **public이 "접근 제한자(access modifier)"라는 공식 용어로 명명됨**: Class Members 챕터에서는 public을 별도 이름 없이 사용했지만, 이번 챕터는 이를 명시적으로 "access modifier"라고 부르며 이것이 없으면 다른 클래스에서 필드에 접근할 수 없다는 점을 재확인함. [S1]

## 🛠️ 적용 사례 (Applied in summary)
동일한 Car 클래스로 두 개의 독립된 객체를 만드는 예제와, Car와 Program을 서로 다른 파일로 분리하되 public으로 필드를 노출하는 예제가 원문에서 직접 실전 활용 사례로 제시됨. [S1]

## 💻 코드 패턴 (Code patterns)
Cross-class field access requires `public` (the access modifier) (C#):
```csharp
// prog2.cs
class Car
{
    public string color = "red";  // public required for cross-class access
}

// prog.cs
class Program
{
    static void Main(string[] args)
    {
        Car myObj = new Car();
        Console.WriteLine(myObj.color);
    }
}
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.82
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[C# Tutorial]]
- **관련 개념:** [[CSharp Class Members]], [[CSharp Constructors]], [[CSharp Access Modifiers]]
- **참조 맥락:** OOP Basics 섹션의 마지막 챕터 — Constructors 섹션으로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — C# Multiple Classes and Objects — https://www.w3schools.com/cs/cs_classes_multi.php

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