> For the complete documentation index, see [llms.txt](https://sisyphus.gitbook.io/project/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sisyphus.gitbook.io/project/c++-notes/scope-resolution-operator.md).

# Scope Resolution Operator ::

可以用于在类外定义类的成员函数

当前面没有scope 时 （::parameter）代表全局

（1）表示“域操作符”例：声明了一个类A，类A里声明了一个成员函数void f()，但没有在类的声明里给出f的定义，那么在类外定义f时， 就要写成void A::f()，表示这个f()函数是类A的成员函数。

（2）直接用在全局函数前，表示是全局函数例：在VC里，你可以在调用API 函数里，在API函数名前加 ::

（3）表示引用成员函数及变量，作用域成员运算符例：System::Math::Sqrt() 相当于System.Math.Sqrt()；

<http://blog.csdn.net/qq_33266987/article/details/53689133>


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