那就是说，如果函数有确定的有效值集合或范围可作为参数，可以将检验参数是否有效的断言放在该函数代码的第一行。

That is, if a function has a certain set or range of valid values for its arguments, an assertion to this effect can be placed as the first line of code in the function.

youdao

方法有两种：创建一个工具包来封装所有本机函数；或者将本机函数直接包含到应用程序中。

This could be done in one of two ways. You could either create a toolkit that encapsulates all the native functions, or directly include native functions into an application.

youdao

有了show_users函数之后，接下来可以创建一个users . php文件，该文件将运行这个函数，并显示系统中所有用户的一个列表，对于每个用户，在用户名的旁边都有一个follow链接。

Now that you have the show_users function, you can create a users.php file that runs it and displays a list of all the users in the system, each with a link that says follow next to the user name.

youdao

有了show_users函数之后，接下来可以创建一个users . php文件，该文件将运行这个函数，并显示系统中所有用户的一个列表，对于每个用户，在用户名的旁边都有一个follow链接。

Now that you have the show_users function, you can create a users.php file that runs it and displays a list of all the users in the system, each with a link that says follow next to the user name.

youdao