单链表的基本操作

#include<iostream>
using namespace std;
class SingleList
{
public:
	int data;
	SingleList *pNext;
};
SingleList* InitSingleList();
SingleList* CreateNode(int data);
void InsertHeadNode(SingleList* pHead, int data);
void InsertTailNode(SingleList *pHead, int data);
void InsertToTarget(SingleList *pHead, int posData, int data);

void DeleteHeadNode(SingleList *pHead);
void DeleteTailNode(SingleList *pHead);
void DeleteTargetNode(SingleList *pHead, int data);

void PrintList(SingleList* pHead);

void SortList(SingleList *pHead);

void ClearList(SingleList *pHead);

void Menu();

int main()
{
	
	SingleList *pHead=InitSingleList();
	while (1)
	{
		system("cls");
		Menu();
		char choic = getchar();
		switch (choic)
		{
		case '1':
			int data;
			cout << "输入要插入的数据" << endl;
			cin >> data;
			InsertHeadNode(pHead,data); 
			system("pause"); break;
		case '2':
			cout << "输入要插入的数据" << endl;
			cin >> data;
			InsertTailNode(pHead,data);
			system("pause"); break;
		case '3':
			int posData;
			cout << "输入在哪个数据之后插入" << endl;
			cin >> posData;
			cout << "输入要插入的数据" << endl;
			cin >> data;
			InsertToTarget(pHead, posData, data); 
			system("pause"); break;
		case '4':
			DeleteHeadNode(pHead); 
			system("pause"); break;
		case '5':
			DeleteTailNode(pHead); 
			system("pause"); break;
		case '6':
			cout << "输入要删除的数据" << endl;
			cin >> data;
			DeleteTargetNode(pHead, data); 
			system("pause"); break;
		case '7':
			SortList(pHead); 	
			system("pause"); break;
		case '8':
			ClearList(pHead);
			system("pause");
			break;
		case '9':
			PrintList(pHead);
			system("pause"); break;
		default:
			break;
		}
		while (getchar() != '\n') {}
	}
	system("pause");
	return 0;
}
SingleList* InitSingleList()	//创建头结点，头结点的指针域就是头指针，用来进行操作链表
{
	//int *p=new int ;
	//int *pArr=new int[10]{0,1,2,3,4,5,6,7,8,9};
	SingleList* pHead = new SingleList;	//new直接返回的就是申请类型的指针，不需要在进行强转了
	if (pHead == nullptr)
	{
		cout << "申请内存失败" << endl;
		exit(0);
		system("pause");
	}
	pHead->pNext = nullptr;
	return pHead;
}
SingleList* CreateNode(int data)	//创建新结点
{
	SingleList* pNew = new SingleList;
	if (pNew == nullptr)
	{
		cout << "申请内存失败" << endl;
		exit(0);
		system("pause");
	}
	pNew->data = data;
}
void InsertHeadNode(SingleList* pHead, int data)//头插法插入一个新结点
{
	SingleList *pNew = CreateNode(data);
	pNew->pNext = pHead->pNext;
	pHead->pNext = pNew;
}
void PrintList(SingleList* pHead)	//打印链表
{
	SingleList* pTemp = pHead->pNext;
	if (pTemp == nullptr)
	{
		cout << "链表为空" << endl;
		return;
	}
	while (pTemp!=nullptr)
	{
		cout << pTemp->data << "\t";
		pTemp = pTemp->pNext;
	}
	cout << endl;
}
void InsertTailNode(SingleList *pHead, int data)	//在尾部插入一个新结点
{
	SingleList *pNew = CreateNode(data);
	SingleList* pTemp = pHead;
	while (pTemp->pNext!= nullptr)
	{
		pTemp = pTemp->pNext;
	}
	pTemp->pNext= pNew;
	pNew->pNext = nullptr;
	cout << "在尾部插入结点执行成功" << endl;
}
//在posData这个数据之后插入data
void InsertToTarget(SingleList *pHead, int posData, int data)
{
	SingleList *pTemp = pHead;
	SingleList *pNew = CreateNode(data);
	while (pTemp->data!=posData)
	{
		if (pTemp->pNext == nullptr)
		{
			cout << "没有找到指定位置" << endl;
			system("pause");
			return;
		}
		pTemp = pTemp->pNext;
	}
	pNew->pNext = pTemp->pNext;
	pTemp->pNext = pNew;
	cout << "在指定位置插入结点成功" << endl;
}
//删除头结点
void DeleteHeadNode(SingleList *pHead)
{
	SingleList *pTemp = pHead->pNext;
	pHead->pNext = pTemp->pNext;
	delete pTemp;
	pTemp = nullptr;
	cout << "删除头结点成功" << endl;
}
//删除尾结点
void DeleteTailNode(SingleList *pHead)
{
	SingleList *pTemp = pHead;
	SingleList *p = pTemp;
	while (pTemp->pNext!= nullptr)
	{
		p = pTemp;
		pTemp = pTemp->pNext;
	}
	p->pNext = nullptr;
	delete pTemp;
	pTemp = nullptr;
	cout << "删除尾结点成功" << endl;
}
//删除指定结点data
void DeleteTargetNode(SingleList *pHead, int data)
{
	SingleList *pTemp = pHead;
	SingleList *p = pTemp;
	while (pTemp->data != data)
	{
		if (pTemp->pNext == nullptr)
		{
			cout << "没有找到指定位置" << endl;
			system("pause");
			return;
		}
		p = pTemp;
		pTemp = pTemp->pNext;
	}
	p->pNext = pTemp->pNext;
	delete pTemp;
	pTemp = nullptr;
	cout << "删除指定结点成功" << endl;
}
//将结点按从小到大的顺序进行排序
void SortList(SingleList *pHead)
{
	for (SingleList *pi = pHead->pNext; pi->pNext != nullptr; pi = pi->pNext)
	{
		for (SingleList *pj = pi; pj!= nullptr; pj = pj->pNext)
		{
			if (pi->data > pj->data)
			{
				int temp = pi->data;
				pi->data = pj->data;
				pj->data = temp;
			}
		}
	}
}
void ClearList(SingleList *pHead)
{
	SingleList *pTemp = pHead;
	SingleList *p=pTemp;
	while (pTemp != NULL)
	{
		//delete p;			//不行,这样的话p和pTemp的指向都为空了，那么还怎么进行指向下一个操作呢
		//p = nullptr;
		p = pTemp;
		pTemp = pTemp->pNext;
		delete p;	//必须在指向下一个结点之后，才可以删除上一个结点，不然就无法指向下一个结点了
		p = nullptr;
	}
	pHead->pNext = nullptr;
	cout << "链表已清空" << endl;
}
void Menu()
{
	cout << "    1、在表头插入数据" << endl;
	cout << "    2、在表尾插入数据" << endl;
	cout << "    3、在指定位置插入数据" << endl;
	cout << "    4、删除头结点" << endl;
	cout << "    5、删除尾结点" << endl;
	cout << "    6、删除指定结点" << endl;
	cout << "    7、链表排序" << endl;
	cout << "    8、清空链表" << endl;
	cout << "    9、打印链表" << endl;

}