///////////////////////////////////////////////////////////////////////////
#include
#include
using namespace std;
class Parents
{
public:
Parents(string n="Parent"){ name = n;}
virtual ~Parents(){}
virtual void Speak()
{
cout << "\tI am " << name << ", I love my children." << endl;
}
void Work()
{
cout << "\tI am " << name <<", I need to work for my family." << endl;;
}
/************** TryParseTo **************/
template
{
T* temp = dynamic_cast
if (temp == NULL) return false;
*outValue = temp;
return true;
}
protected:
string name;
};
class Children : public Parents
{
public:
Children(string n="Child"):Parents(n){ }
virtual ~Children(){}
virtual void Speak()
{
cout << "\tI am " << name << ", I love my parents." << endl;
}
/*
**Children inherit Work() method from parents,
**it could be treated like part-time job.
*/
void Study()
{
cout << "\tI am " << name << ", I need to study for future." << endl;;
}
private:
//string name; //Inherit "name" member from Parents
};
class Stranger
{
public:
Stranger(string n="stranger"){name = n;}
virtual ~Stranger(){}
void Self_Introduce()
{
cout << "\tI am a stranger" << endl;
}
void Speak()
{
//cout << "I am a stranger" << endl;
cout << "\tDo not talk to "<< name << ", who is a stranger." << endl;
}
private:
string name;
};
int main()
{
Children * parsedChild;
Parents * parsedParent;
Stranger * parsedStranger;
Parents * mother = new Parents("Mother who pretend to be a my daugher");
if(mother->TryParseTo
parsedChild->Speak();
else
cout << "Parents parse to Children failed" << endl;
delete mother;
mother = new Children("Daughter who pretend to be a my mother");
if(mother->TryParseTo
parsedChild->Speak();
else
cout << "Parents parse to Children failed" << endl;
delete mother;
Children * son = new Children("Son who pretend to be a my father");
if(son->TryParseTo
parsedParent->Speak();
else
cout << "Children parse to Parents failed" << endl;
if(son->TryParseTo
parsedStranger->Speak();
else
cout << "Children parse to Stranger failed" << endl;
delete son;
//pointer of child class could pointer to base class object
/*
* son = new Parents("Father who pretend to be a my son");
if(son->TryParseTo
parsedParent->Speak();
else
cout << "Parse failed" << endl;
delete son;
*/
return 0;
}
/********************* Result *********************/
//Parents parse to Children failed
// I am Daughter who pretend to be a my mother, I love my parents.
// I am Son who pretend to be a my father, I love my parents.
//Children parse to Stranger failed
这段代码中使用到的类跟dynamic_cast一文中使用的基本一样，只是在基类中多了一个模板方法：
template
{
T* temp = dynamic_cast
if (temp == NULL) return false;
*outValue = temp;
return true;
}
该方法需要指定的目标类型，将自身指针转换成目标指针。转换成功，则将结果赋值给相应的变量，并返回真值；若失败则返回假值，不改变指针变量。因为要让外部的指针变量能够接受到改值，因此不得不使用指向指针的指针。
因为在基类中以公共结果的形式出现，所以每一个子类都继承了该方法，无论是基类的对象还是子类的对象都可以调用该方法。而该方法又不是虚方法，因此不并不希望子类去修改它。只是因为方法是模板方法，可能在编译的时候需要多花一些时间。
由于引用必须在定义时就赋值，并且dynamic_cast对于基于引用的转换不成功时将抛出异常，因此对于基于引用的转换，我还没有想出有什么好的山寨形式。
从测试代码的结果也可以看出，对于该发放的调用都是成功有效的。