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目录

一.顺序表下的串的实现

index函数：

代码部分及运行结果： 

二.单链表下的串的实现

index函数：

代码部分及运行结果：

***说明***

1.本代码基于书上第二章线性表和4.3节串的实现结合书写。

2.本篇文章分为两个部分，分别为用顺序表实现串和用单链表实现串；书上提供的代码是用顺序表实现串，小编自己给出了用单链表实现串的方法；

3.本代码对书上代码做了一个小小修改，template中只传入了一个参数class temp，更加精简。

4.顺序表VS单链表：顺序表的实现函数写起来比较精简，但是缺点是控制条件需要考虑仔细；

单链表的实现函数控制条件相对统一易于思考，但是写起来比较繁琐，并且和顺序表中部分代码重复。

***说明完毕***

一.顺序表下的串的实现

index函数：

template<class temp>
int seqlist<temp>::index(seqlist<temp>& t)
{
	int i = 1, j = 1;
	while (i <= this->getlength() && j <= t.getlength())
	{
		if (this->get(i) == t.get(j))
		{
			i++;
			j++;
		}
		else
		{
			i = i - j + 2;
			j = 1;
		}
	}
	if (j >= t.getlength())
		return i +1 - j;
	else
		return -1;
}

代码部分及运行结果： 

#include <iostream>
using namespace std;
#define N 100
template<class temp>
class seqlist
{
private:
	temp data[N];
	int length;
public:
	seqlist() { length = 0; }
	seqlist(temp a[], int n);
	int getlength() { return length; }
	void printlist();
	void insert(int i, temp x);
	temp del(int i);
	temp get(int i);
	int locate(temp x);
	int index(seqlist& t);
};

template <class temp>
seqlist<temp>::seqlist(temp a[], int n)
{
	if (n > N)throw "数组长度超过顺序表最大长度";
	for (int i = 0; i < n; i++)
		this->data[i] = a[i];
	this->length = n;
}

template<class temp>
void seqlist<temp>::printlist()
{
	cout << "按序号依次遍历线性表中各个数据元素:" << endl;
	for (int i = 0; i < this->length; i++)
		this->data[i].print();
	cout << endl;
}

template<class temp>
void seqlist<temp>::insert(int i, temp x)
{
	if (this->length >= N)throw"上溢异常";
	if (i < 1 || i >= this->length + 1)throw"位置异常";
	for (int j = this->length; j >= i; j--)
		this->data[j] = this->data[j - 1];
	this->data[i - 1] = x;
	this->length++;
}

template<class temp>
temp seqlist<temp>::del(int i)
{
	if (this->length == 0)throw"下溢异常";
	if (i<1 || i>this->length)throw"位置异常";
	temp x = data[i - 1];
	for (int j = i; j < this->length; j++)
		data[j - 1] = data[j];
	this->length--;
	return x;
}


template<class temp>
temp seqlist<temp>::get(int i)
{
	if (i<1 || i>this->length)throw"查找位置非法";
	return this->data[i - 1];
}

template<class temp>
int seqlist<temp>::locate(temp x)
{
	for (int i = 0; i < this->length; i++)
		if (this->data[i] == x)return(i + 1);
	return 0;
}

template<class temp>
int seqlist<temp>::index(seqlist<temp>& t)
{
	int i = 1, j = 1;
	while (i <= this->getlength() && j <= t.getlength())
	{
		if (this->get(i) == t.get(j))
		{
			i++;
			j++;
		}
		else
		{
			i = i - j + 2;
			j = 1;
		}
	}
	if (j >= t.getlength())
		return i +1 - j;
	else
		return -1;
}

int main()
{
	system("color 0A");
	char a[] = "hello world";
	char b[] = "good";
	char c[] = "ello";
	seqlist<char>seqa(a, strlen(a));
	seqlist<char>seqb(b, strlen(b));
	seqlist<char>seqc(c, strlen(c));
	cout << seqa.index(seqa) << endl;//1
	cout << seqa.index(seqb) << endl;//-1
	cout << seqa.index(seqc) << endl;//2
	return 0;
}

二.单链表下的串的实现

index函数：

注意看解释！

template<class temp>
int linklist<temp>::index(linklist<temp>&t)
{
	node<temp>* p = this->front->next;
	node<temp>* q = t.front->next;
	node<temp>* headp = this->front->next;//需要有一个主串标记点
	node<temp>* headq = t.front->next;//需要有一个模式串标记点
	int countp = 0, countq = 0;//和顺序表思路雷同
	while (p != NULL && q != NULL)//但是判断条件好简单
	{
		if (p->data == q->data)
		{
			p = p->next; countp++;//不要怕麻烦因为不用动脑子
			q = q->next; countq++;
		}
		else
		{
			p = headp->next;//主串游标指针重新指向主串标记点的下一个节点
			headp = headp->next;//标记点也随之后移
			q = headq;//模式串游标指针重新指向模式串的标记点
			countp = countp - countq + 1;//和顺序表思路雷同
			countq = 0;
		}
	}
	if (q == NULL)
		return countp - countq + 1;//和顺序表思路雷同
	else
		return -1;//和顺序表思路雷同
}

代码部分及运行结果：

#include<iostream>
using namespace std;
template<class temp>
struct node
{
	temp data;
	node<temp>* next;
};

template <class temp>
class linklist
{
private:
	node<temp>* front;
public:
	linklist()
	{
		this->front = new node<temp>;
		this->front->next = nullptr;
	}
	linklist(temp a[], int n);
	~linklist();
	void printlist();
	int getlength() ;
	node<temp>* get(int i);
	int locate(temp x);
	void insert(int i, temp x);
	temp del(int i);
	int index(linklist<temp>&t);
};

//头插法
template<class temp>
linklist<temp>::linklist(temp a[], int n)
{
	this->front = new node<temp>;
	this->front->next = NULL;
	for (int i = n - 1; i >= 0; i--)
	{
		node<temp>* s = new node<temp>;
		s->data = a[i];
		s->next = this->front->next;
		this->front->next = s;
	}
}

template<class temp>
linklist<temp>::~linklist()
{
	node<temp>* p = this->front;
	while (p != NULL)
	{
		this->front = p;
		p = p->next;
		delete front;
	}
}

template<class temp>
void linklist<temp>::printlist()
{
	node<temp>* p = this->front->next;
	while (p != NULL)
	{
		p->data.print();//数据域中的print方法(需要用户自定义)
		p = p->next;
	}
	cout << endl;
}
template<class temp>
int linklist<temp>::getlength()
{
	node<temp>* p = this->front->next;
	int cnt = 0;
	while (p != NULL)
	{
		cnt++;
		p = p->next;
	}
	return cnt;
}

//按位置查找，返回地址
template<class temp>
node<temp>* linklist<temp>::get(int i)
{
	node<temp>* p = this->front->next;
	int j = 1;
	while (p != NULL && j != i)
	{
		p = p->next;
		j++;
	}
	return p;
}

//按值查找，返回位置
template<class temp>
int linklist<temp>::locate(temp x)
{
	node<temp>* p = this->front->next;
	int j = 1;
	while (p != NULL)
	{
		if (p->data == x)return j;
		p = p->next;
		j++;
	}
	return -1;//如果没有找到，返回无效值
}

template <class temp>
void linklist<temp>::insert(int i, temp x)
{
	node<temp>* p = this->front;
	if (i != 1)
		p = get(i - 1);//get(i - 1)表示要插入的位置的前一个结点地址
	if (p != NULL)
	{
		node<temp>* s = new node<temp>;
		s->data = x;
		s->next = p->next;
		p->next = s;
	}
	else
	{
		cout << "插入位置错误:" << endl;
		exit(0);
	}
}

template<class temp>
temp linklist<temp>::del(int i)
{
	node<temp>* p = this->front;
	if (i != 1)p = get(i - 1);
	node<temp>* q = p->next;
	p->next = q->next;
	temp x = q->data;
	delete q;
	return x;
}

template<class temp>
int linklist<temp>::index(linklist<temp>&t)
{
	node<temp>* p = this->front->next;
	node<temp>* q = t.front->next;
	node<temp>* headp = this->front->next;
	node<temp>* headq = t.front->next;
	int countp = 0, countq = 0;
	while (p != NULL && q != NULL)
	{
		if (p->data == q->data)
		{
			p = p->next; countp++;
			q = q->next; countq++;
		}
		else
		{
			p = headp->next;
			headp = headp->next;
			q = headq;
			countp = countp - countq + 1;
			countq = 0;
		}
	}
	if (q == NULL)
		return countp - countq + 1;
	else
		return -1;
}

int main()
{
	system("color 0A");
	char a[] = "hello world";
	char b[] = "good";
	char c[] = "ello";
	linklist<char>linka(a, strlen(a));
	linklist<char>linkb(b, strlen(b));
	linklist<char>linkc(c, strlen(c));
	cout << linka.index(linka) << endl;//1
	cout << linka.index(linkb) << endl;//-1
	cout << linka.index(linkc) << endl;//2
	return 0;
}