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以下代码的输出结果是什么?

#include<iostream>
using namespace std;
 class A
 {
 protected:
	 int m_data;
 public:
	 A(int data = 0):m_data(data){}
	 int GetData()
	 {
		 return doGetData();
	 }
	 virtual int doGetData()
	 {
		 return m_data;
	 }
 };


 class B : public A
 {
 protected:
	 int m_data;
 public:
	 B(int data = 1):m_data(data){}
	 virtual int doGetData()
	 {
		 return m_data;
	 }
 };


 class C : public B
 {
 protected:
	 int m_data;
 public:
	 C(int data = 5):m_data(data){}
 };


 int main()
 {
	 C c(10);
	 cout<<c.GetData()<<endl;
	 cout<<c.A::GetData()<<endl;
	 cout<<c.B::GetData()<<endl;
	 cout<<c.C::GetData()<<endl;
	 cout<<c.doGetData()<<endl;
	 cout<<c.A::doGetData()<<endl;
	 cout<<c.B::doGetData()<<endl;
	 cout<<c.C::doGetData()<<endl;
	 cout<<c.GetData()<<endl;
	 system("pause");
	 return 0;
 }