---
id: cpp-for-loop-nested
title: "C++ Nested Loops"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["inner outer loop", "multiplication table", "C++ 중첩 반복문"]
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", "loops", "nested-loops"]
raw_sources: ["https://www.w3schools.com/cpp/cpp_for_loop_nested.asp"]
applied_in: []
github_commit: ""
---

# [[CPP Nested Loops]]

## 🎯 한 줄 통찰 (One-line insight)
The identical multiplicative execution-count annotation from C's Nested Loops chapter reappears unchanged (outer runs 2 times, inner runs "6 times (2 * 3)," not additive 5) — reconfirming that nested-loop cost scales multiplicatively in C++ exactly as it did in C, which is why nested loops remain the natural fit for 2D structures like tables and matrices in both languages. [S1]

## 🧠 핵심 개념 (Core concepts)
- **Nested loop** — a loop placed entirely inside another loop's body; the inner loop runs to completion once for EVERY iteration of the outer loop. [S1]
- **Multiplicative execution count** — total inner-body executions = (outer iterations) × (inner iterations). [S1]
- **Natural fit for 2D data** — tables, matrices, multi-dimensional structures. [S1]

## 📖 세부 내용 (Details)
- Basic nesting with explicit iteration-count annotation: `for (int i = 1; i <= 2; ++i) { cout << "Outer: " << i << "\n"; for (int j = 1; j <= 3; ++j) { cout << " Inner: " << j << "\n"; } }` — outer runs 2 times, inner runs 6 times total (2×3). [S1]
- Multiplication table via nested loops: `for (int i = 1; i <= 3; i++) { for (int j = 1; j <= 3; j++) { cout << i * j << " "; } cout << "\n"; }` — produces `1 2 3 / 2 4 6 / 3 6 9`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- 현재까지 발견된 모순 사항 없음 (No contradictions found in available sources). C 챕터와 동일한 곱셈 관계 및 예제가 확인됨.

## 🛠️ 적용 사례 (Applied in summary)
3x3 구구단표를 중첩 for 루프로 출력하는 예제가 원문에서 직접 실전 활용 사례로 제시됨. [S1]

## 💻 코드 패턴 (Code patterns)
A multiplication table built from two nested for loops (C++):
```cpp
for (int i = 1; i <= 3; i++) {
  for (int j = 1; j <= 3; j++) {
    cout << i * j << " ";
  }
  cout << "\n";
}
// 1 2 3
// 2 4 6
// 3 6 9
```

## ✅ 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 For Loop Foreach]], [[CPP For Loop RealLife]], [[C For Loop Nested]]
- **참조 맥락:** 중첩 for 루프 — for 루프 실전 예제(For Loop RealLife) 챕터로 이어짐.

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

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