---
id: c-operators-arithmetic
title: "C Arithmetic Operators"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["integer division", "increment decrement", "C 산술 연산자"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.86
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["c", "programming-language", "w3schools", "operators", "arithmetic"]
raw_sources: ["https://www.w3schools.com/c/c_operators_arithmetic.php"]
applied_in: []
github_commit: ""
---

# [[C Arithmetic Operators]]

## 🎯 한 줄 통찰 (One-line insight)
Dividing two `int` values ALWAYS produces an `int` result, silently truncating any decimal — `10 / 3` gives `3`, not `3.33` — and the ONLY way to get a decimal result is to make at least the operand types `float`/`double` (`10.0 / 3` gives `3.333...`), meaning integer division isn't a rounding behavior to configure, it's an unavoidable consequence of the operand types chosen. [S1]

## 🧠 핵심 개념 (Core concepts)
- **Seven core arithmetic operators** — `+` (add), `-` (subtract), `*` (multiply), `/` (divide), `%` (modulus/remainder), `++` (increment), `--` (decrement). [S1]
- **Integer division truncation** — dividing two `int`s always yields an `int`, discarding any decimal remainder; use `float`/`double` operands to get a decimal result. [S1]
- **Increment/decrement round-trip** — incrementing then decrementing the same variable (or vice versa) returns it to its original value. [S1]

## 📖 세부 내용 (Details)
- All seven operators demonstrated together: `int x = 10; int y = 3; x + y; // 13`, `x - y; // 7`, `x * y; // 30`, `x / y; // 3`, `x % y; // 1`, plus `++z`/`--z` on a separate variable. [S1]
- Integer vs decimal division contrast: `int a = 10; int b = 3; printf("%d\n", a / b); // 3 (integer division)` versus `double c = 10.0; double d = 3.0; printf("%f\n", c / d); // 3.333...`. [S1]
- Real-life counting example: `int peopleInRoom = 0; peopleInRoom++; peopleInRoom++; peopleInRoom++; // 3 people enter, count = 3` then `peopleInRoom--; // 1 leaves, count = 2`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **정수 나눗셈의 소수점 절삭**: int끼리 나누면 항상 int 결과가 나와 소수점이 버려진다는 점이 명시되며, 소수 결과를 원하면 최소 한쪽을 float/double로 만들어야 한다는 해결책이 함께 제시됨. [S1]

## 🛠️ 적용 사례 (Applied in summary)
방에 들어오고 나가는 사람 수를 ++/--로 세는 카운터 예제가 원문에서 직접 실전 활용 사례로 제시됨. [S1]

## 💻 코드 패턴 (Code patterns)
Integer division truncates; use float/double operands for a decimal result (C):
```c
int a = 10;
int b = 3;
printf("%d\n", a / b); // Integer division, result is 3

double c = 10.0;
double d = 3.0;
printf("%f\n", c / d); // Decimal division, result is 3.333...
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.86
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[C Tutorial]]
- **관련 개념:** [[C Operators]], [[C Operators Assignment]]
- **참조 맥락:** 산술 연산자 — 대입 연산자(Operators Assignment) 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — C Arithmetic Operators — https://www.w3schools.com/c/c_operators_arithmetic.php

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