#include<iostream>
using namespace std;
#include<assert.h>

class Person
{
public:
	void showClassNmae()
	{
		cout << "this is class Person" << endl;
	}

	void showPersonAge()
	{	
		//为了防止对空指针的访问
		/*assert(this);*/
		if (this == NULL)
		{
			return;
		}
		cout <<this-> m_Age << endl;//这里的m_Age实质上是类成员的m_Age,也就是this->m_Age;
	}

	int m_Age;
};

void test01()
{
	Person* p = NULL;
	p->showClassNmae();
	p->showPersonAge();//这里对NULL进行了访问，导致程序出错 p对象中的this指向空，空的m_Age肯定是出错了
}

int main()
{
	test01();
}