---
# System prepended metadata

title: Data Stracture
tags: [Computer Scient]

---

# Data Stracture
###### tags: `Computer Scient`
# Netmask

![](https://i.imgur.com/aAUlOkz.png)


```
A:  mask:12  255.240.0.0 換算 二進位
A:  11111111.11110000.00000000.00000000

B:  172.25.4.72 換算 二進位
B:  10101100.00011001.00000100.01001000


A與B 做 and 運算
11111111.11110000.00000000.00000000
10101100.00011001.00000100.01001000
10101100.00010000.00000000.00000000

10101100.00010000.00000000.00000000 
轉換成 10 進位
172.16.0.0 

172.25.4.72 這個網段 是 172.16.0.0 
```

Reference
> https://www.163.com/dy/article/F9AA4H3V0538056H.html