链表操作

#include <QtCore/QCoreApplication> #include<iostream>
using namespace std;
typedef struct node //定义一个结构体，在c++中也是一个类
{
int val;
struct node* pNext;
}NODE,*PNODE;

//NODE == struct node 定义一个新的接点
//PNODE == struct node* 定义一个指向这个接点的指针

class MyList //创建一个类
{
private:
PNODE pHead;//struct node* pHead

public:
MyList() //构造函数，构造一个空链表头指针
{
this->pHead = NULL;
}

~MyList() //析构函数
{
while(this->pHead!=NULL)
{
PNODE pTemp = pHead->pNext;
delete pHead;
pHead = pTemp;
}
}

void Init() //初始化链表
{
int a;
char ans;

PNODE pTail,pNew;

do
{
cout<<"请输入一个节点值：";
cin>>a;

if(pHead == NULL)//判断链表中是否有元素（是否是空链表）
{
pHead = new NODE;
pHead->val = a;
pHead->pNext = NULL;

pTail = pHead;
}
else
{
pTail = pHead;
while(pTail->pNext!=NULL)//把pTail移动到尾部
{
pTail = pTail->pNext;
}

pNew = new NODE;//new一个新的接点来接受新输入的值
pNew->val = a;
pNew->pNext = NULL;

pTail->pNext = pNew;
pTail = pTail->pNext;
}

cout<<"继续吗？(Y/N): ";
cin>>ans;

}while(ans=='Y'||ans=='y');
}

void Add(int val) //向链表中追加值方法
{
if(pHead == NULL)
{
pHead = new NODE;
pHead->val = val;
pHead->pNext = NULL;
}
else
{
PNODE pTemp = pHead;
while(pTemp->pNext!=NULL)
{
pTemp = pTemp->pNext;
}

PNODE pNew = new NODE;
pNew->val = val;
pNew->pNext = NULL;

pTemp->pNext = pNew;
}
}

int DelAt(int k) //删除链表中的元素的方法
{
PNODE p1,p2,pTemp;

if(pHead == NULL)
{
return -1;
}

if(k<0 || k>this->GetNodeCnt()-1)
{
return -1;
}

if(this->GetNodeCnt() == 1)
{
delete pHead;
pHead = NULL;
return 0;
}

if(k==0)
{
pTemp = pHead;
pHead = pTemp->pNext;
delete pTemp;
return 0;
}

if(k == this->GetNodeCnt()-1)
{
PNODE p,pTemp;

p = pHead;
while(p->pNext->pNext!=NULL)
{
p = p->pNext;
}

pTemp = p->pNext;

p->pNext = NULL;
delete pTemp;

return 0;
}

p1 = pHead;
int i=0;
while(i<k-1)
{
p1 = p1->pNext;
i++;
}

pTemp = p1->pNext;
p2 = p1->pNext->pNext;

p1->pNext = p2;
delete pTemp;
return 0;
}

int InsertAt(int val,int k)//向链表中插入元素，约定在k之前插入
{
PNODE p1,p2,pNew,pTemp;

if(pHead == NULL)//链表为空
{
return -1;
}

if(k<0 || k>this->GetNodeCnt()-1)//k越界
{
return -1;
}

if(k==0)//在头节点之前插入
{
pTemp = pHead;

pNew = new NODE;
pNew->val = val;
pNew->pNext = NULL;

pHead = pNew;

pNew->pNext = pTemp;

return 0;
}

p1 = pHead;
int i =0;
while(i<k-1)
{
p1 = p1->pNext;
i++;
}

p2 = p1->pNext;

pNew = new NODE;
pNew->val = val;
pNew->pNext = NULL;

p1->pNext = pNew;
pNew->pNext = p2;

return 0;

}

int Find(int val) //按输入的值查找方法
{
int i=0;
PNODE pTemp = pHead;
while(pTemp != NULL)
{
if(pTemp->val == val)
{
return i;
}
pTemp = pTemp->pNext;
i++;
}
return -1;
}

void Travel() //遍历单链表中的元素
{
PNODE pTemp = this->pHead;

while(pTemp!=NULL)
{
cout<<pTemp->val<<" ";
pTemp = pTemp->pNext;
}
cout<<endl;
}

int GetNodeCnt() //获取单链表中元素的个数
{
int cnt=0;
PNODE pTemp = pHead;

while(pTemp!=NULL)
{
cnt++;
pTemp = pTemp->pNext;
}

return cnt;
}

void sort() //把单链表中的元素排序
{
int n = this->GetNodeCnt();
PNODE p1,p2;

for(int i=0;i<n-1;i++)
{
p1 = pHead;

for(int j=0;j<n-1-i;j++)
{
p2 = p1->pNext;

if(p1->val < p2->val)
{
int k = p1->val;
p1->val = p2->val;
p2->val = k;
}

p1 = p1->pNext;
}
}
}
};


//测试主函数


int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
MyList list;

for(int i=0;i<10;i++)
{
list.Add(i);
}

list.Travel();

list.sort();

list.Travel();
return a.exec();
}