学步园

#include <iostream>
using namespace std;
typedef int T;
class List{
	struct Node{
		T data;
		Node* next;
		Node(const T& d, Node* next=NULL):data(d),next(next)
		{}
	};
	Node* head;	
	int len;
public:
	~List(){clear();}
	List():head(),len(){}
	int size()const{return len;}
	void travel()const{
		Node* p = head;
		while(p){
			cout << p->data << ' ';
			p = p->next;
		}
		cout << endl;
	}
	void clear(){
		Node* p = head, * q;
		while(p){
			q = p->next;
			delete p;
			p = q;		}
		head = NULL, len = 0;
	}
	Node*& getptr(int n){
		if(n<0||n>len) 
			n = len;		
		if(n==0) return head;
		Node* p = head;
		for(int i=1; i<n; i++)
			p = p->next;
		return p->next;
	}
	void insert(const T& d, int n){
		Node*& p=getptr(n);
		Node* q = new Node(d,p);
		p = q;
		++len;
	}
	void erase(int n){		Node*& p = getptr(n);
		if(p){
			Node* q = p;
			p = p->next;
			delete q;
			--len;
		}
	}
	void remove(const T& d){
		Node*& p = find(d);
		if(p){
			Node* q = p;
			p = p->next;
			delete q;
			--len;
		}
	}
	Node*& find(const T& d){
		if(len==0||head->data==d) return head;
		Node* p = head;
		while(p->next&&p->next->data!=d) p = p->next;
		return p->next;
	}
	void update(const T& oldv, const T& newv){
		Node* p = find(oldv);
		if(p){p->data = newv;}
	}
	T& front(){return head->data;}
	T& back(){return getptr(len-1)->data;}
	void push_front(const T& d){insert(d,0);}
	void push_back(const T& d){insert(d,len);}
	void pop_front(){erase(0);}
	void pop_back(){erase(len-1);}
	void sort(){}
	void reverse(){}
	T& operator[](int index)throw(const char*){
		if(index<0||index>=len) throw "越界";
		return getptr(index)->data;
	}
};
int main()
{
	List l;
	l.insert(1,0);l.insert(2,0);l.insert(3,0);
	l.insert(4,4);l.insert(5,4);l.insert(6,6);
	l.travel();
	l.erase(3);
	l.remove(2);
	l.travel();
	l.update(5,6);
	l.travel();
	for(int i=0; i<l.size(); i++)
		cout << l[i] << ',';
	cout << endl;

	return 0;
}

PS:供面试和笔试，或者想熟悉下LIST实现的童鞋看看