結論：JAVA裡面的內部類比C++裡面的內部類好用

JAVA程式碼

1.OutSide.class

2._Main.class

C++程式碼

1.OutSide.h

2.._Main.cpp

下面是JAVA程式碼

OutSide.class

package ABoutInnerClass;

public class OutSide
{
	public int a=1;
	public static int b=10000;
	public void print()
	{
		System.out.println("OutSide-print called");
	}
	public InSide Create()
	{
		InSide a=new InSide();
		return a;
	}
	public class InSide
	{
		public int c=2;
		public void print()
		{
			System.out.println("InSide-print called");
			System.out.println("a of OutSide is "+b);
			System.out.println("OutSide-a is "+a);
			System.out.println("OutSide-a is "+OutSide.this.a);
		}
	}
}
 

package ABoutInnerClass;

public class _Main
{

	public static void main(String[] args)
	{
		OutSide outside=new OutSide();
		outside.print();
		
		OutSide.InSide inside=outside.new InSide();
		inside.print();
		
		OutSide.InSide inside2=outside.Create();
		inside2.print();	
	}
}

執行結果：

OutSide-print called
InSide-print called
a of OutSide is 10000
OutSide-a is 1
OutSide-a is 1
InSide-print called
a of OutSide is 10000
OutSide-a is 1
OutSide-a is 1

Outside.h

#include <stdio.h>

class OutSide
{
public:
	int a; 
	static int static_a;
	OutSide() :a(1)
	{
	}
	void print()
	{
		printf_s("OutSide-print called\n");
	}

	class InSide
	{
	public:
		int b;
		InSide():b(2)
		{
		}
		void print()
		{
			printf_s("InSide-print called\n");
			printf_s("a of OutSide is %d\n", OutSide::static_a);
		}
	};
	InSide* Create()
	{
		InSide *a = new InSide();
		return a;
	}
};
int OutSide::static_a = 1000;
 

#include "Demo.h"
#include <string>

void main()
{
	OutSide *outside = new OutSide();
	outside->print();

	OutSide::InSide *inside = new OutSide::InSide();
	inside->print();

	OutSide::InSide *inside2 = outside->Create();
	inside2->print();
	
	getchar();
	delete inside2;
	delete outside;
	delete inside;
}

個人覺得C++中內部類用得不是很多，可以分開寫，時程式碼變得簡單，可讀性變強