---
id: cpp-conditions-nested
title: "C++ Nested If"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["if inside if", "dependent conditions", "C++ 중첩 if"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.83
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["cpp", "programming-language", "w3schools", "conditions", "nested-if"]
raw_sources: ["https://www.w3schools.com/cpp/cpp_conditions_nested.asp"]
applied_in: []
github_commit: ""
---

# [[CPP Nested If]]

## 🎯 한 줄 통찰 (One-line insight)
The same short-circuit benefit from C's Nested If chapter applies unchanged — the citizenship check (`isCitizen`) is never even evaluated if `age >= 18` is false, meaning nesting still functions as a genuine short-circuit optimization in C++, not just visual grouping of related checks. [S1]

## 🧠 핵심 개념 (Core concepts)
- **Nested if** — placing an `if` inside another `if`'s block, so the inner condition is only checked when the outer condition already holds. [S1]
- **Dependent condition modeling** — naturally expresses "check B only if A holds." [S1]
- **Depth caution** — avoid nesting too deeply, as it hurts readability; often combined with `else`/`else if`. [S1]

## 📖 세부 내용 (Details)
- Basic two-level nesting: `int x = 15; int y = 25; if (x > 10) { cout << "x is greater than 10\n"; if (y > 20) { cout << "y is also greater than 20\n"; } }`. [S1]
- Voting + citizenship real-life example: `int age = 20; bool isCitizen = true; if (age >= 18) { cout << "Old enough to vote.\n"; if (isCitizen) { cout << "And you are a citizen, so you can vote!\n"; } else { cout << "But you must be a citizen to vote.\n"; } } else { cout << "Not old enough to vote.\n"; }`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- 현재까지 발견된 모순 사항 없음 (No contradictions found in available sources). C 챕터와 동일한 중첩 if 및 단축 평가 특성이 확인됨.

## 🛠️ 적용 사례 (Applied in summary)
투표 가능 연령(18세 이상)을 먼저 확인하고, 그 안에서만 시민권 여부를 추가로 확인하는 예제가 원문에서 직접 실전 활용 사례로 제시됨. [S1]

## 💻 코드 패턴 (Code patterns)
An inner condition (citizenship) checked only when the outer condition (age) already holds (C++):
```cpp
int age = 20;
bool isCitizen = true;
if (age >= 18) {
  cout << "Old enough to vote.\n";
  if (isCitizen) {
    cout << "And you are a citizen, so you can vote!\n";
  } else {
    cout << "But you must be a citizen to vote.\n";
  }
} else {
  cout << "Not old enough to vote.\n";
}
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.83
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[C++ Tutorial]]
- **관련 개념:** [[CPP Conditions Logical]], [[CPP Conditions RealLife]], [[C Conditions Nested]]
- **참조 맥락:** 중첩 if — 조건문 실전 예제(Conditions RealLife) 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — C++ Nested If — https://www.w3schools.com/cpp/cpp_conditions_nested.asp

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