单链表的基本操作

#include<iostream>
#include<stdio.h>
#include<stdlib.h>
#include<string>
using namespace std;

//定义节点结构体
typedef struct ListNod
{
int data;
struct ListNod *next;
}listnode,*linklist;

//初始化链表
void Creatlist(linklist *head)
{
if ((*head = (linklist)malloc(sizeof(listnode)))==NULL)
exit (-1);
(*head)->next = NULL;
}

//求链表长度
int length(linklist head)
{
listnode *p;
int count = 1;
p = head->next;
while (p->next != NULL)
{
p = p->next;
++count;
}
return count;
}

//检查链表是否为空
int listempty(linklist head)
{
if (head->next == NULL)
return 1;
else
return 0;
}

//遍历链表
listnode *get(linklist head,int i)
{
listnode *p;
int j=0;
if (listempty(head))
return NULL;
if (i < 1)
return NULL;
p = head;
while (p->next != NULL && j < i)
{
p = p->next;
j++;
}
if (j == i)
return p;
else
return NULL;
}

//从链表中查找与给定元素值相同的元素在表中的位置
int find(linklist head, int e)
{
listnode *p;
int i=1;
p = head->next;
while (p)
{

if (p->data == e)
{
return i;

}
else
{
p = p->next;
++i;
}
if (!p)
return 0;
}

}

//向链表中插入指定元素
int insert(linklist head, int i, int e)
{
listnode *p, *pre;
int j = 0;
pre = head;
while (pre->next != NULL && j < i - 1)
{
pre = pre->next;
++j;
}
if (j != i - 1)
{
cout << "插入位置错误";
return 0;
}
if ((p = (listnode *)malloc(sizeof(listnode))) == NULL)
exit (-1);
p->data = e;
p->next = pre->next;
pre->next = p;
return 1;
}

//从链表中删除指定元素
int delect(linklist head,int i, int *e)
{
listnode *p, *pre;
int j = 0;
pre = head;
while (pre->next != NULL && pre->next->next != NULL)
{
pre = pre->next;
j++;
}
if (j != i - 1)
{
cout << "删除位置错误";
return 0;
}
p = pre->next;
*e = p->data;
pre->next = pre->next;
free(p);
return 1;
}

//销毁链表
void destroy(linklist head)
{
listnode *p, *q;
p = head;
while (p->next != NULL)
{
q = p;
p = p->next;
free(q);
}
}

int main()
{
int i;
int a[] = { 12, 13, 14, 52, 15, 32, 56, 55,35, 45};
linklist A;
listnode *p;
Creatlist(&A);

//初始化链表
for (i = 1; i <= sizeof(a) / sizeof(a[0]); i++)
{
if (insert(A, i, a[i - 1]) == 0)
{
cout << "插入失败";
return 0;
}
}

//统计并输出元素
cout << "单链表A中的元素个数有" << length(A) << "个：";
for (i = 1; i <=length(A); i++)
{
p = get(A, i);
if (p)
cout << p->data << ' ';
}
cout << endl;

//查找元素
int k;
cout << "输入要查找元素：";
cin >> k;
int c = find(A, k);
cout << "位置是："<< c << endl;

//插入元素并显示插入后的结果
int e,j,m;
cout << "输入要插入的元素和位置：";
cin >> e >> j;
m = insert(A, j, e);
cout << "成功" << endl;
cout << "单链表A中插入元素后的元素个数有" << length(A) << "个：";
for (i = 1; i <= length(A); i++)
{
p = get(A, i);
if (p)
cout << p->data << ' ';
}
cout << endl;

//销毁链表
cout << "是否销毁链表？" << endl;
cout << "请输入‘1(销毁) or 0(不销毁)’" << endl;
int w;
cin >> w;
switch (w)
{
case 1:{
destroy(A);
cout << "成功！"<<endl;
}; break;
case 0:return 0; break;
default:
return 0;

}
return 0;
}