单向循环链表创建、遍历、插入、删除、查找（按位置，按元素值）、清空、销毁

SinglyLinkedCirculayList.h

#include "stdafx.h"
#include "iostream"
using namespace std;
typedef struct LNode {
int data;
struct LNode *next;
}LNode, *LinkedList;
//创建链表
bool createLinkedList(LinkedList &L, int i) {
if (i < 1)
{
cout << "输入不合法！" << endl;
exit(EXIT_FAILURE);
}
L = (LinkedList)malloc(sizeof(LNode));
if (!L)
{
cout << "内存分配失败!" << endl;
exit(EXIT_FAILURE);
}
LinkedList p, q;
L->next = L;
p = L;
int j;
for (j = 0; j < i; j++)
{
q = (LinkedList)malloc(sizeof(LNode));
if (!q)
{
cout << "内存分配失败！" << endl;
exit(EXIT_FAILURE);
}
cout << "请输入第" << j + 1 << "个元素：";
cin >> q->data;
p->next = q;
q->next = L;
p = q;
}
return true;
}
//获取链表的长度
int getListLength(LinkedList &L) {
if (L->next == L)
{
cout << "链表为空" << endl;
return 0;
}
LinkedList p;
p = L;
int j = 0;
while (p->next != L)
{
j++;
p = p->next;
}
return j;
}
//打印链表
void printLinkedList(LinkedList &L) {
LinkedList p;
p = L;
if (L->next == L)
{
cout << "链表为空！" << endl;
exit(EXIT_FAILURE);
}
for (int i = 0; i < getListLength(L); i++)
{
p = p->next;
cout << p->data << " ";
}
cout << endl;
}
//在第i个位置之前插入元素
bool insertListElem(LinkedList &L, int i, int num) {
if (i<1 || i>getListLength(L))
{
cout << "输入不合法！" << endl;
exit(EXIT_FAILURE);
}
LinkedList p, q;
p = L;
for (int j = 0; j < i - 1; j++) //定位到要插入结点的前一个
{
p = p->next;
}
q = (LinkedList)malloc(sizeof(LNode));
if (!q)
{
cout << "内存分配失败！" << endl;
exit(EXIT_FAILURE);
}
q->data = num;
q->next = p->next;
p->next = q;
return true;
}
//删除第i个元素
bool deleteListElem(LinkedList &L, int i) {
if (i<1 || i>getListLength(L))
{
cout << "输入不合法！" << endl;
exit(EXIT_FAILURE);
}
LinkedList p,q;
p = L;
int j;
for (j = 0; j < i - 1; j++) //定位到要删除的结点的前一个
{
p = p->next;
}
q = p->next;
p->next = p->next->next;
free(q);
return true;
}
//查找并返回第i个位置的元素
int getElem(LinkedList &L, int i) {
if (i<1 || i>getListLength(L))
{
cout << "输入不合法！" << endl;
exit(EXIT_FAILURE);
}
LinkedList p;
p = L;
int j;
for (j = 0; j < i; j++)
{
p = p->next;
}
return p->data;
}
//在链表中查找节点值等于num的位置，并返回
int searchElem(LinkedList &L, int num) {
LinkedList p;
p = L->next;
int j = 1;
while ((p->data != num) &
4000
amp;& (j <= getListLength(L)))
{
p = p->next;
j++;
}
if (j <= getListLength(L))
{
return j;
}
else
{
cout << "查找无该值！" << endl;
return false;
}
}
//销毁链表
bool destroylinkedlist(LinkedList &L) {
LinkedList p, q;
p = q = L->next;
while (p != L)
{
p = p->next;
free(q);
q = p;
}
free(L);
return true;
}
//清空链表
bool clearList(LinkedList &L) {
LinkedList p, q;
p =q= L->next;
if (L == NULL)
{
return false;
}
while (p != L)
{
p = p->next;
free(q);
q = p;
}
L->next = L;
return true;
}

main.cpp
#include "stdafx.h"
#include "SinglyLinkedCirculayList.h"
int main()
{
LinkedList list1;
int length;
cout << "请输入要创建的链表的长度：";
cin >> length;
createLinkedList(list1, length);
cout << "当前链表为：";
printLinkedList(list1);
int i, elem;
cout << "要插入的位置为：";
cin >> i;
cout << "要插入的元素的大小为：";
cin >> elem;
insertListElem(list1,i,elem);
cout << "当前链表为：";
printLinkedList(list1);
cout << "要删除的元素的位置为：";
cin >> i;
deleteListElem(list1,i);
cout << "当前链表为：";
printLinkedList(list1);
cout << "要查找的元素位置为：";
cin >> i;
cout << "该位置元素的值为：";
cout<<getElem(list1,i)<<endl;
cout << "要查找的元素大小为：";
cin >> elem;
cout << "该元素所在的位置为：";
cout << searchElem(list1,elem)<<endl;
cout << "清空链表";
clearList(list1);
cout << "打印当前链表：";
printLinkedList(list1);
system("pause");
return 0;
}