What do two colons mean in C language?
The meaning of two colons (::) in C language: Scope resolution operator: resolves names in the scope, allowing access to names outside the current scope. Nested type name: Specify the name of the nested type, used to refer to the nested type.
The meaning of two colons in C language
In C language, the double colon (::) has the following meaning Two meanings:
1. Scope resolution operator
Double colon is used to resolve names in the scope. It allows access to names outside the current scope. For example:
int main() { int x = 10; { int x = 20; cout << ::x; // 输出 10 } return 0; }
In the inner scope, the x variable declared in the outer scope is accessed through ::x.
2. Nested type name
Double colon is used to specify the name of the nested type. For example:
namespace myNamespace { class MyClass { struct InnerClass { // ... }; }; }
To refer to a nested type, use a double colon:
myNamespace::MyClass::InnerClass innerObject;
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