1.global scope (global scope)
for example
int a;
void test ()
{
int a = ::a;//Use global variable a to assign value to local variable a
}
2.class scope (class scope)
for example
class A
{
public:
int test();
}
int A::test()//Indicates that test belongs to A
{
return 0;
}
3. Namespaces
3.1 Namespace simple declaration and invocation:
namespace na
{
int a;
char c;
}
call na::a
3.2 Nested use
namespace ns1
{
int a;
char c = 10;
void fun();
int Add(int a, int b)
{
return a + b;
}
namespace ns2
{
int b;
}
}
If you want to call b then: ns1::ns2:b
3.3: Aliasing namespaces
namespace Television
{...}
namespace Tv=Television;
Tv:: can call members in Television
3.4: Using using xxx::xxx
using ns1::a; If this statement is used, the place where a is used does not need to add the :: symbol
3.4.2: Using using namespace xxx
using namespace ns1 If you use this statement, you can directly use the internal members of ns1 without adding the :: symbol
3.5: Nameless namespaces
namespace
{
void fun();
}
Only use the fun function within this file