线性表实现——单链表

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define OK 1
#define ERROR 0
typedef int Status;
typedef int ElemType;

typedef struct Node
{
    ElemType data;
    struct Node* next;
}Node;

typedef struct Node* LinkList;

Status InitList(LinkList* L)  //初始化操作，建立一个空的线性表.想把头指针里面的值改掉，所以传个头指针的地址
{
    *L = (LinkList)malloc(sizeof(Node));
    if (!(*L))
        return ERROR;
    (*L)->next = NULL;
    return OK;
}
Status ListEmpty(LinkList L)  //若线性表为空，返回true,否则返回false
{
    if (L->next == NULL)
        return OK;
    return ERROR;
}
Status ClearList(LinkList* L) //清空线性表
{
    LinkList p = (*L)->next;
    LinkList q;
    while(p!= NULL)
    {
        q = p;
        p = p->next;
        free(q);
    }
    (*L)->next = NULL;
    return OK;
}
Status GetElem(LinkList L,int  i,ElemType *e)  //查找线性表中的第i个位置的元素值，并赋值给e
{
    int j = 0;
    while (L && j < i)
    {
        L = L->next;
        j++;
    }
    if (!L || j > i)
        return ERROR;
    *e = L->data;
    return OK;
}
Status LocateElem(LinkList L, ElemType e) //查找线性表L中与给定值e相等的元素，如果查找成功，则返回第一个相同的元素在L中的下标；否则，返回0表示失败
{
    int i=1;
    LinkList p = L->next;
    while (p != NULL && p->data != e)
    {
        p = p->next;
        i++;
    }
    if (!p)
        return ERROR;
    return i;
}
Status ListInsert(LinkList* L, int i, ElemType e)  //在线性表L的第i个位置插入元素e
{
    LinkList p, q;
    p = *L;
    int j = 1;
    while (p && j<i)    //尾部插入时，p指向最后一个值，而j=i-1
    {
        p = p->next;
        j++;
    }
    if (!p || j > i)
        return ERROR;
    
    q = (LinkList)malloc(sizeof(Node));
    q->data = e;
    q->next = p->next;
    p->next = q;
            
    return ERROR;
}
Status ListDelete(LinkList*L, int i, ElemType* e) //删除线性表L中第i个位置元素，并用e返回其值
{
    LinkList p, q;
    p = *L;
    int j = 1;
    //while (p && j<i)
    while (p->next && j<i)
    {
        p = p->next;
        j++;
    }
    //if (!p || j > i)
    if (!(p->next) || j > i)
        return ERROR;
    q = p->next;
    *e = q->data;
    p->next = q->next;
    free(q);
    return OK;
}
Status CreateListHead(LinkList *L, int n)
{
    LinkList p;
    int i;
    (*L) = (LinkList)malloc(sizeof(Node));
    (*L)->next = NULL;
    for (i = 0; i < n; i++)
    {
        p = (LinkList)malloc(sizeof(Node));
        p->data = i;
        p->next = (*L)->next;
        (*L)->next = p;
    }
    return OK;
}
Status CreateListTail(LinkList *L, int n)
{
    LinkList p;
    int i;
    (*L) = (LinkList)malloc(sizeof(Node));
    //(*L)->next = NULL;
    LinkList q = (*L);
    for (i = 0; i < n; i++)
    {
        p = (LinkList)malloc(sizeof(Node));
        p->data = i+10;
        q->next = p;
        q = p;
    }
    q->next = NULL;
    return OK;
}
Status visit(ElemType n)
{
    printf("-> %d  ", n);
    return OK;
}
Status ListTraverse(LinkList L)
{
    LinkList p = L->next;
    while (p != NULL)
    {
        visit( p->data);
        p = p->next;
    }
    return OK;
}

int ListLength(LinkList L)  //返回线性表L的长度
{
    int i = 0;
    LinkList p = L->next;
    while (p != NULL)
    {
        i++;
        p = p->next;
    }
    return i;
}

int main()
{
    LinkList L;
    Status i,j;
    char opp='-1';
    ElemType e;
    int pos = 1;
    int k=0;

    i = InitList(&L);
    printf("链表L初始化完毕，ListLength(L)=%d\n\n", ListLength(L));

    printf("\n1.遍历操作 \n2.插入操作  \n3.删除操作 \n4.获取结点数据\n5.查找某个数是否在链表中 \n6.头插法创建链表 \n7.尾插法创建链表 \n8.置空链表 \n0.退出 \n请选择你的操作：\n");

    while (opp != '0') {
        scanf_s("%c", &opp);
        switch (opp) {
        case '1':
                ListTraverse(L);
                printf("\n");
                break;

        case '2':
                srand((unsigned)time(NULL));
                for (j = 1; j <= 10; j++)
                {
                        i = ListInsert(&L, 1, rand() % 100);
                }
                printf("在L的表头依次插入10个随机数后：");
                ListTraverse(L);
                printf("\n");
                printf("链表L创建完毕，ListLength(L)=%d\n\n", ListLength(L));
                break;
        case '3':
                printf("要删除第几个元素？");
                scanf_s("%d", &pos);
                ListDelete(&L, pos, &e);
                printf("删除第%d个元素成功，现在链表为：\n", pos);
                ListTraverse(L);
                printf("\n");
                break;

        case '4':
                printf("你需要获取第几个元素？");
                scanf_s("%d", &pos);
                GetElem(L, pos, &e);
                printf("第%d个元素的值为：%d\n", pos, e);
                printf("\n");
                break;
        case '5':
                printf("输入你需要查找的数：");
                scanf_s("%d", &pos);
                k = LocateElem(L, pos);
                if (k)
                    printf("第%d个元素的值为%d\n", k, pos);
                else
                    printf("没有值为%d的元素\n", pos);
                printf("\n");
                break;
        case '6':
                CreateListHead(&L, 10);
                printf("整体创建L的元素(头插法)：\n");
                ListTraverse(L);
                printf("\n");
                break;

        case '7':
                CreateListTail(&L, 10);
                printf("整体创建L的元素(尾插法)：\n");
                ListTraverse(L);
                printf("\n");
                break;

        case '8':
                i = ClearList(&L);
                printf("\n清空L后：ListLength(L)=%d\n", ListLength(L));
                ListTraverse(L);
                printf("\n");
                break;

        case '0':
                exit(0);
        }
    }
}