extern
「extern」的意思
n. 非住院医生；不住院的医院员工；外勤修女；大学实习生; v. 驱逐; adj. 外面的；外来的；...
n.走读生,走读医学研究生adj.<古>外(面)的,外来的
「extern」的用法
extern外部的 - 在PHP中，extern用于声明一个在其他文件中定义的变量。
「extern」的例句
The extern keyword is used to declare a variable that is defined in another file.
extern关键字用于声明在另一个文件中定义的变量。
extern int x;
extern int x;
In this case, the variable x is defined in another file and is being declared as extern in the current file.
在这种情况下，变量x在另一个文件中定义，并且在当前文件中被声明为extern。
This allows multiple files to access and modify the same variable.
这允许多个文件访问和修改同一个变量。
It's important to note that the variable must be defined before it can be declared as extern.
需要注意的是，变量必须在声明为extern之前被定义。
Using extern can help in organizing code and managing shared data across different files.
使用extern可以帮助组织代码并管理不同文件之间的共享数据。
However, it's generally recommended to use include or require statements to include other files and access their variables directly.
然而，通常建议使用include或require语句来包含其他文件并直接访问它们的变量。
This approach provides better encapsulation and avoids potential naming conflicts.
这种方法提供了更好的封装，并避免了潜在的命名冲突。
In summary, while extern can be useful in certain scenarios, it's often better to use include or require for accessing variables from other files.
总之，虽然extern在某些情况下很有用，但在大多数情况下，使用include或require来访问其他文件中的变量会更好。