单链表基本操作

//单链表基本操作
#include <iostream>
using namespace std;

//#define ElemType int
typedef int ElemType;

typedef struct LNode {
    ElemType data;
    struct LNode *next;   // (递归定义)  指向后继节点
}LinkList;

//头插法建表
void CreateListF(LinkList *&List, ElemType a[], int n) {
    LinkList *s;
    List = (LinkList *)malloc(sizeof(LinkList));
    List->next = NULL;
    for (int i = 0; i < n; i++) {
        s = (LinkList*)malloc(sizeof(LinkList));
        s->data = a[i];
        s->next = List->next;
        List->next = s;
    }
}


//尾插法建表
void CreateListR(LinkList *&List, ElemType a[], int n) {
    LinkList *s, *r;
    List = (LinkList *)malloc(sizeof(LinkList));
    r = List;
    List->next = NULL;
    for (int i = 0; i < n; i++) {
        s = (LinkList *)malloc(sizeof(LinkList));
        s->data = a[i];
        r->next = s;
        r = s;
    }
    r->next = NULL;
}

//初始化单链表
void InitList(LinkList *&list) {
    list = (LinkList *)malloc(sizeof(LinkList));
    list->next = NULL;
}

//销毁单链表
void DestroyList(LinkList *&list) {
    LinkList *p = list, *q = list->next;
    while (q != NULL) {
        free(p);
        p = q;
        q = q->next;
    }
    free(p);
}

//判断单链表是否为空
bool ListEmpty(LinkList *list) {
    return (list->next == NULL);
}

//求单链表的长度
int ListLength(LinkList *list) {
    int n = 0;
    LinkList * p = list;
    while (p->next) {
        n++;
        p = p->next;
    }
    return n;
}

//输出单链表
void DispList(LinkList *list) {
    LinkList *p = list->next;
    while (p != NULL) {
        cout << p->data << "  ";
        p = p->next;
    }
    cout << endl;
}

//求单链表中某值元素的位置
int LocateElem(LinkList *list, ElemType e) {
    int i = 1;
    LinkList *p = list ->next;
    while (p != NULL && p->data != e) {
        i++;
        p = p->next;
    }
    if (p == NULL)
        return (0);
    else 
        return (i);
}



//求单链表中某个位置元素的值
bool GetElem(LinkList*list, int i, ElemType &e) {
    LinkList * p = list;
    int j = 0;
    while (j < i && p->next != NULL) {
        j++;
        p = p->next;
    }
    if (p == NULL)
        return false;
    else {
        e = p->data;
        return true;
    }
}


//插入数据元素
bool ListInsert(LinkList *&list, int i, ElemType e) {
    int j = 0;
    LinkList *p = list, *s;
    while (j < i - 1 && p != NULL) {
        j++;
        p = p->next;
    }
    if (p == NULL) 
        return false;
    else {
        s = (LinkList *)malloc(sizeof(LinkList));
        s->data = e;
        s->next = p->next;
        p->next = s;
        return true;
    }
    
    
}

//删除数据元素
bool ListDelete(LinkList *&list, int i, ElemType &e) {
    int j = 0;
    LinkList *p = list, *q;
    while (j < i - 1 && p != NULL) {
        j++;
        p = p->next;
    }
    if (p == NULL)
        return false;
    else {
        q = p->next;
        if (q == NULL)
            return false;
        e = q->data;
        p->next = q->next;
        free(q);
        return true;
    }
}


int main() {
    const int n = 7;
    int a[n];
    cout << "Input " << n << " numbers:";
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    LinkList *lista, *listb;
    InitList(lista);
    InitList(listb);
    CreateListF(lista, a, n);
    cout << "Input " << n << " numbers:";
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    CreateListR(listb, a, n);
    cout << "头插法(lista)：";
    DispList(lista);
    cout << "尾插法(listb)：";
    DispList(listb);
    DestroyList(listb);
    cout << endl << endl;
    
    int len = ListLength(lista);
    cout << "Lista的长度" << len << endl;
    cout << endl << endl;
    
    
    int m;
    cout << "输入要查询的元素的值(lista)：" ;
    cin >> m;
    int loca = LocateElem(lista, m);
    cout << m << "第一次出现在" << loca << "位置" << endl;
    cout << endl << endl;
    
    
    cout << "输入要查询的元素的位置(lista)：";
    cin >> loca;
    GetElem(lista, loca, m);
    cout << "第" << loca << "个元素的值为" << m<< endl;
    cout<< endl << endl;
    
    
    cout << "输入要插入的位置和数值(lista)：";
    cin >> loca >> m;
    if (ListInsert(lista, loca, m))
        DispList(lista);
    else
        cout << "插入失败！" << endl;
    cout << endl << endl;
    
    cout << "输入要删除的位置(lista)：";
    cin >> loca;
    if (ListDelete(lista, loca, m))    {
        cout << "删除的元素值为" << m << endl << "更新后的链表为：";
        DispList(lista);
        cout << endl << endl;
    }
    else cout << "删除失败!" << endl;
    DestroyList(lista);
}