ep8_9.cpp

这里有大量的c语言习题呢！真的是题海哦

/*8.9	采用纯虚函数实现多态性来建立通用的双向链表派生类。参考【例8.10】和【例7.7】。*/
#include "ep8_9.h"
#include<string>
using namespace std;
class StringObject:public Object{
	string sptr;
public:
	StringObject();
	StringObject(string);
	~StringObject();
	bool StringObject::operator>(Object & obj);//虚函数
	bool StringObject::operator!=(Object & obj);//虚函数
	void Print();
};
StringObject::StringObject(){sptr="";}
StringObject::StringObject(string s){sptr=s;}
StringObject::~StringObject(){cout<<"删除字符串类"<<endl;}
bool StringObject::operator>(Object & obj){//虚函数
	StringObject & temp=(StringObject &)obj;//必须转换
	return sptr>temp.sptr;
}
bool StringObject::operator!=(Object & obj){//虚函数
	StringObject & temp=(StringObject &)obj;//必须转换
	return sptr!=temp.sptr;
}
void StringObject::Print(){cout<<sptr<<'\t';}//虚函数

int main(){
	DblNode * P1;
	StringObject* p;
	DblList list1,list2,list3;
	char *a[5]={"dog","cat","bear","sheep","ox"},*sp="cat";
	int i;
	for(i=0;i<5;i++){
		p=new StringObject(a[i]);//建立数据对象
		P1=list1.CreatNode();//建立结点
		P1->Linkinfo(p);//数据对象连接到结点
		list1.InsertFront(P1);//向前生成list1
		p=new StringObject(a[i]);
		P1=list2.CreatNode();
		P1->Linkinfo(p);
		list2.InsertRear(P1);//向后生成list2
	}
	list1.PrintList();
	cout<<"list1长度："<<list1.Length()<<endl;
	list2.PrintList();
	cout<<"要求删除的字符串\"cat\""<<endl;
	p=new StringObject(sp);//为了程序的通用性只能多一次转换
	P1=list1.Find(*p);
	delete p;
	if(P1!=NULL){
		cout<<"删除cat:"<<endl;
		P1=list1.DeleteNode(P1);
		delete P1;
		list1.PrintList();
		cout<<"list1长度："<<list1.Length()<<endl; 
	}
	else cout<<"未找到"<<endl;
	cout<<"清空list1:"<<endl;
	list1.MakeEmpty();//清空list1
	list1.PrintList();
	for(i=0;i<5;i++){
		p=new StringObject(a[i]);
		P1=list3.CreatNode();
		P1->Linkinfo(p);
		list3.InsertOrder(P1);//升序创建list3
	}
	list3.PrintList();
	cout<<"程序结束："<<endl;
	return 0;
}