关于虚函数的两道读程序题

 读程序，写出输出的结果：

关于虚函数和多态，可参考一篇不错的文章http://blog.youkuaiyun.com/moxiaomomo/article/details/6826412

1、virtual意味着运行时再决定调用哪个函数。

#include<iostream>
using namespace std;
 
class Base
{
public:
         Base(){}
         virtual ~Base(){}

         void func1(){ 
			 cout << "func1 in base~" << endl; 
			 func2();
		 }

         virtual void func2(){
			 cout<<"func2 in base~"<<endl;
		 }
};

class Derive: public Base
{
public:
         Derive(){}
         ~Derive(){}

		 void func1(){
			 cout<<"func1 in Derive~"<<endl; 
			 func2();
		 }

         void func2(){
			 cout<<"func2 in Derive~"<<endl;
		 }
};

int main()
{

         Derive d;
         Base* b=&d;
         b->func1();

         return 0;
}

2、当通过基类的指针删除派生类的对象，而基类又没有虚析构函数时，结果将是不确定的。实际运行时经常发生的是，派生类的析构函数永远不会被调用，那么派生类的资源也将无法释放。

#include<iostream>
using namespace std;
 
class base
{
public:
	base(){cout << "construct in base" << endl;};
	 ~base() {cout << "disconstruct in base" << endl;};
};
class derive: public base
{
public:
	derive();
	~derive();
private:
	char *buf;
};
derive::derive() {
	buf = (char *)malloc(100);
	cout << "cosntruct in derive" << endl;
}
derive::~derive() {
	if(buf)
		delete buf;
	cout << "disconstruct in derive" << endl;
}

int main()
{
	base  *pa = new derive();
	delete pa;

	return 0;
}