局部类的相关问题

1.局部类不能定义静态成员函数
#include <iostream>
using namespace std;
int main(void)
{
    class test
    {
        static int a;
    };
    cout << sizeof(test) << endl;
}
编译报错如下：
a.cpp: In function ‘int main()’:
a.cpp:10:20: error: local class ‘class main()::test’ shall not have static data member ‘int main()::test::a’ [-fpermissive]
         static int a;
                   ^

2.局部类允许访问外围作用域中的枚举和静态变量
#include <iostream>
using namespace std;

enum RR
{
    FD = 100
};
static int a = 10;

void f(void)
{
    enum {ABC = 400};
    static int b = 20;

    class A
    {
        int print ()
        {
            cout << FD << endl;
            cout << a << endl;

            cout << ABC << endl;
            cout << b << endl;
        }
    };
}

int main(void)
{
    f();
    return 0;
}

3.外围函数对局部类的保护成员函数和私有成员函数没有访问权限
#include <iostream>

int f (void)
{
    class A
    {
        public:
            int sum()
            {
                cout << "i am public" << endl;
                return 0;
            }
        protected:
            int time()
            {
                cout << "i am protected" << endl;
                return 0;
            }
        private:
            int now()
            {
                cout << "i am private" << endl;
            }
    };
    A a;
    a.sum();
    a.time(); // error
    a.now(); // error

}

int main(void)
{
    f();
    return 0;
}

4.局部类的嵌套

#include <iostream> using namespace std; void func( void )
{ //函数func()内定义一个局部类MyClass  class MyClass
     { public: void f1( void )
            {
                 cout << "MyClass::f1( )" << endl;
            } //----------------------------------类中有类:局部类的嵌套  class Cla
            { public: void f2( void )
                   {
                        cout << "MyClass::Cla::f2( )" << endl;
                   }
            }; //------------------------------------------  }; //访问局部类中的成员函数  MyClass rs;
     rs.f1( ); //访问局部类中的嵌套类的成员函数  MyClass::Cla cl;
     cl.f2( );
} int main( void )
{
    func( );
    
 	system( "PAUSE" ); return EXIT_SUCCESS;
}

5.类中有类

#include <iostream> using namespace std; class A
{ public: void funA( void )
       {
            cout << "A::fA( )" << endl;
       } //---------------------类中有类:在另一个类内部定义一个类  class B
       { public: void funB( void )
              {
                    cout << "B::fB( )" << endl;
              }
      }; //-------------------------------  }; int main( void )
{
    A objA; //外部类实例化一个对象objA  objA.funA( ); //objA对象调用类A成员函数  A::B objB; //内部类实例化一个对象objB  objB.funB( );//objB对象调用类B成员函数  system( "PAUSE" ); return EXIT_SUCCESS;
}

6.