---
id: cpp-user-input
title: "C++ User Input"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["cin extraction operator", "C++ 사용자 입력"]
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: ["cpp", "programming-language", "w3schools", "user-input", "cin"]
raw_sources: ["https://www.w3schools.com/cpp/cpp_user_input.asp"]
applied_in: []
github_commit: ""
---

# [[CPP User Input]]

## 🎯 한 줄 통찰 (One-line insight)
`cin` and `cout` form a deliberately symmetric pair — the source explicitly pairs their pronunciations ("see-out"/"see-in") and their operators (`<<` insertion / `>>` extraction) as mirror images of each other, meaning learning `cout <<` from the Output chapter directly transfers to `cin >>` here: same object-and-operator pattern, just reversed in data direction and operator angle. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`cin`** — a predefined variable that reads keyboard input, using the EXTRACTION operator `>>` (mirror of `cout`'s insertion operator `<<`). [S1]
- **Both belong to `<iostream>`** — `cin` and `cout` are both part of the same standard input/output streams library. [S1]
- **Building a simple calculator** — chaining two `cin >>` reads plus arithmetic demonstrates a complete interactive program. [S1]

## 📖 세부 내용 (Details)
- Basic numeric input: `int x; cout << "Type a number: "; cin >> x; cout << "Your number is: " << x;`. [S1]
- A two-number calculator: `int x, y, sum; cin >> x; cin >> y; sum = x + y; cout << "Sum is: " << sum;`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- 현재까지 발견된 모순 사항 없음 (No contradictions found in available sources).

## 🛠️ 적용 사례 (Applied in summary)
두 숫자를 입력받아 합을 계산하는 간단한 계산기 프로그램이 원문에서 직접 실전 활용 사례로 제시됨. [S1]

## 💻 코드 패턴 (Code patterns)
A simple calculator built from two cin reads and an arithmetic sum (C++):
```cpp
int x, y, sum;
cout << "Type a number: ";
cin >> x;
cout << "Type another number: ";
cin >> y;
sum = x + y;
cout << "Sum is: " << sum;
```

## ✅ 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:** [[CPP Scope]], [[CPP Date]], [[CPP Strings Input]]
- **참조 맥락:** 사용자 입력 — 날짜와 시간(Date) 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — C++ User Input — https://www.w3schools.com/cpp/cpp_user_input.asp

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