> For the complete documentation index, see [llms.txt](https://whs3-doge5k.gitbook.io/smartcontract-security-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://whs3-doge5k.gitbook.io/smartcontract-security-docs/basics/3.-evm/evm-2/undefined/uint-n-bytes-n-bool-n-address-n.md).
# uint\[n], bytes\[n], bool\[n], address\[n]
{% hint style="info" %}
배열의 크기가 정해진 경우는 정적 타입으로 간주한다.
{% endhint %}
### **특징**
| 항목 | 설명 |
| ------------ | ----------------------------------------------------------------------------------- |
| **타입** | 정적 타입 (크기 고정) |
| **크기** | n x 변수 바이트 |
| **슬롯 사용 방식** |
변수의 크기에 따라 결정됨: – uint256\[3] → 3개 슬롯 사용 – bool\[3] → 1개 슬롯 안에 packing
|
| **패킹 여부** |
대부분은 packing 안됨 단, bool\[n], uint8\[n], bytes1\[n] 등은 packing 발생
|
| **접근 방식** | array\[i] → base\_slot + i 방식으로 접근(packing이 없을 경우) |
***
### **예시 1**
```solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract Example6 {
uint[3] public nums;
constructor() {
nums[0] = 10;
nums[1] = 20;
nums[2] = 30;
}
}
```
```
// 스토리지
address: 0x0000000000000000000000000000000000000000000000000000000000000000
0x000000000000000000000000000000000000000000000000000000000000000a
address: 0x0000000000000000000000000000000000000000000000000000000000000001
0x0000000000000000000000000000000000000000000000000000000000000014
address: 0x0000000000000000000000000000000000000000000000000000000000000002
0x000000000000000000000000000000000000000000000000000000000000001e
```
슬롯 0, 1, 2에 각각 uint\[0], uint\[1], uint\[2] 값이 저장되었다.
* nums\[0]: 0x000000000000000000000000000000000000000000000000000000000000000a
* nums\[1]: 0x0000000000000000000000000000000000000000000000000000000000000014
* nums\[2]: 0x000000000000000000000000000000000000000000000000000000000000001e
고정된 배열은 각각 독립적인 슬롯 하나를 할당 받는다.
***
### **예시 2**
```solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract Example7 {
bool[3] public flags;
constructor() {
flags[0] = true;
flags[1] = false;
flags[2] = true;
}
}
```
```
address: 0x0000000000000000000000000000000000000000000000000000000000000000
0x0000000000000000000000000000000000000000000000000000000000010001
```
bool 타입 배열은 하나의 슬롯에 packing 된다.
* flags\[0] = 0x01
* flags\[1] = 0x02
* flags\[2] = 0x01
***
### **예시 3**
```solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract Example8 {
address[3] public addresses;
constructor() {
addresses[0] = msg.sender;
addresses[1] = tx.origin;
addresses[2] = msg.sender;
}
}
```
```
address: 0x0000000000000000000000000000000000000000000000000000000000000000
0x0000000000000000000000005a933567a53548b7dcb37df4af2d4b6816a476e4
address: 0x0000000000000000000000000000000000000000000000000000000000000001
0x0000000000000000000000005a933567a53548b7dcb37df4af2d4b6816a476e4
address: 0x0000000000000000000000000000000000000000000000000000000000000002
0x0000000000000000000000005a933567a53548b7dcb37df4af2d4b6816a476e4
```
address 타입 배열은 각각 개별 슬롯을 할당받는다.
base slot + i 인덱스를 통해 각각의 address 배열 값에 접근할 수 있다.
