---
id: cpp-conditions-reallife
title: "C++ If ... Else Examples"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["real-life if else", "even or odd example", "C++ 조건문 실전 예제"]
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: ["cpp", "programming-language", "w3schools", "conditions", "real-life-example"]
raw_sources: ["https://www.w3schools.com/cpp/cpp_conditions_reallife.asp"]
applied_in: []
github_commit: ""
---

# [[CPP If ... Else Examples]]

## 🎯 한 줄 통찰 (One-line insight)
The five worked scenarios (door code, positive/negative/zero, voting age, nested citizenship check, even/odd via `%`) mirror C's real-life if/else chapter almost verbatim — the sole notable omission is C's temperature-banding example, meaning this chapter consolidates the same core parity-check and equality-check idioms while trimming one example from the C original. [S1]

## 🧠 핵심 개념 (Core concepts)
- **This chapter is a compilation** — worked real-life if/else scenarios consolidating patterns from every prior Conditions sub-chapter. [S1]
- **Door-code check** — a single `==` equality check gating access. [S1]
- **Positive/negative/zero classification** — a three-way `if`/`else if`/`else` chain. [S1]
- **Even/odd via modulus** — `num % 2 == 0` is the standard parity-check idiom, same as in C. [S1]

## 📖 세부 내용 (Details)
- Door code check: `int doorCode = 1337; if (doorCode == 1337) { cout << "Correct code.\nThe door is now open.\n"; } else { cout << "Wrong code.\nThe door remains closed.\n"; }`. [S1]
- Positive/negative/zero: `int myNum = 10; if (myNum > 0) { cout << "The value is a positive number.\n"; } else if (myNum < 0) { cout << "The value is a negative number.\n"; } else { cout << "The value is 0.\n"; }`. [S1]
- Even/odd check: `int myNum = 5; if (myNum % 2 == 0) { cout << myNum << " is even.\n"; } else { cout << myNum << " is odd.\n"; }`. [S1]

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

## 🛠️ 적용 사례 (Applied in summary)
도어락 코드 확인, 숫자 부호 판별, 투표 연령, 짝/홀수 판별 등이 원문에서 직접 제시되며, 각각이 조건문 섹션 전체를 종합한 실전 활용 사례다. [S1]

## 💻 코드 패턴 (Code patterns)
The standard parity-check idiom using the modulus operator (C++):
```cpp
int myNum = 5;
if (myNum % 2 == 0) {
  cout << myNum << " is even.\n";
} else {
  cout << myNum << " is odd.\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:** 0.82
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[C++ Tutorial]]
- **관련 개념:** [[CPP Conditions Nested]], [[CPP Operators Arithmetic]], [[CPP Switch]]
- **참조 맥락:** 조건문 섹션 마지막 — switch 문(Switch) 섹션으로 이어짐.

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

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