Cracking The Coding Interview 2.2

#include <iostream>

#include <string>

using namespace std;

class linklist

{

private:

	class node

	{

	public:

		node(){}

		string data;

		node * next;

	};

	node *head;

	int size;

public:

	linklist()

	{

		head = new node;

		size = 0;

	}

	/***整表建立***/

	void Create(string *s,int size)

	{

		if (s==NULL || size == 0)

		{

			return;

		}

		node *p = new node;

		p->data = s[0];

		head->next = p;

		for (int i = 1; i<size; i++)

		{

			node *t = new node;

			t->data = s[i];

			p->next = t;

			p=p->next;

		}

		p->next = NULL;

		this->size = size;

	}

	/***整表刪除***/

	void Clear()

	{

		for (int i = 1;i<size+1; i++)

		{

			Delete(i);

		}

		head = NULL;

		size = 0;

	}

	/***第i[i為1，2....size,下同]個元素前插入string型e***/

	void Insert(int i, string e)

	{

		if (i<0 || i>size)

		{

			return;

		}

		int t = i - 1;

		node *p = head;

		node *pn = p->next;

		while(t!=0)

		{

			p = p->next;

			pn = pn->next;

			t--;

		}

		node *ee = new node;

		ee->data = e;

		ee->next = pn;

		p->next = ee;

		size ++;

	}

	/****獲取第i個元素的值,並返回該值**/

	string Get(int i)

	{

		if (i<=0 || i>size)

		{

			return "Error: You input wrong num.";

		}

		int t = i;

		node *p =head;

		while(t!=0)

		{

			p = p->next;

			t--;

		}

		return p->data;

	}

	/***刪除第i個元素***/

	void Delete(int i)

	{

		if (i<0 || i>size)

		{

			return;

		}

		int t = i - 1;

		node *p = head;

		node *pn = p->next;

		while(t!=0)

		{

			p = p->next;

			pn = pn->next;

			t--;

		}

		p->next = pn->next;

		delete pn;

		size --;

	}

	void Display()

	{

		if (head==NULL)

		{

			return;

		}

		node * p;

		p=head->next;

		/*for (int i =0; i<size; i++)

		{

		cout<<p->data<<"  ";

		p=p->next;

		}*/

		while(p!=NULL)

		{

			cout<<p->data<<"  ";

			p=p->next;

		}

		cout<<endl;

	}

	~linklist()

	{

	}

	/*****Implement an algorithm to find the nth to last element of a singly linked list.*****/

	string GetLastN(int n)

	{

		if (n<0||n>size)

		{

			return "Error: Wrong Number";

		}

		int i = 0;

		node *p = head->next;

		node *q = head->next;

		while(i<n)

		{

			p=p->next;

			i++;

		}

		while(p!=NULL)

		{

			p=p->next;

			q=q->next;

		}

		return q->data;

	}

};

int main()

{

	string str[8]={"sos","OMG","sos","OMG","OMG","OMG","fof","fof"};

	linklist s;

	s.Create(str,8);

	s.Display();

	/*s.Insert(2,"bingo");

	s.Display();

	s.Delete(3);

	s.Display();

	cout<<s.Get(1)<<endl;

	s.Clear();

	s.Display();*/

	//s.RemoveDupulicate();

	cout<<s.GetLastN(6);

	//s.Display();

	return 0;

}