#include<iostream.h>
template<class T>
class LinearList
{
	public:
		virtual bool IsEmpty()const=0;
		virtual int Length()const=0;
		virtual bool Find(int i,T&x)const=0;
		virtual int Search(T x)const=0;
		virtual bool Insert(int i,T x)=0;
		virtual bool Delete(int i)=0;
		virtual bool Update(int i,T x)=0;
		virtual void Output(ostream& out)const=0;
	protected:
		int n;
};