单链表的操作

#include "stdafx.h"
#include<iostream>

using namespace std;

typedef int ElemType;

typedef enum Status {
    success, fail, fatal, rangeerror, overflow
}Status;

typedef struct node {
    ElemType data; //数据域
    struct  node * next; //指针域
}ListNode,*ListNodePtr;

typedef ListNodePtr List, *ListPtr;


Status List_Init(ListPtr L) {
    Status status = fatal;
    *L = (ListNodePtr)malloc(sizeof(ListNode));/*分配存储空间*/
    if (*L) {
        (*L)->next = NULL;
        status = success;
    }
    return status;
}

void List_Clear(ListPtr L) {
    ListNodePtr p = *L;
    ListNodePtr q = p->next;
    while (q) {
        p->data = q->data;
        free(q);
        q = p->next;
    }
}

void List_Destroy(ListPtr L) {
    List_Clear(L);
    free(L);//删除头节点
}

bool List_Empty(ListPtr L) {
    return (*L)->next == NULL;
}

int List_Size(ListPtr L) {
    int length = 0;
    ListNodePtr p = (*L)->next;
    while (p) {
        length++;
        p = p->next;
    }
    return length;
}

Status List_SetPosition(ListPtr L, int pos, ListNodePtr * ptr) {
    Status status = fail;
    ListNodePtr p = *L;
    int i = 0;
    while (ptr && i < pos) {
        i++;
        p = p->next;
    }
    if (p && i == pos) {
        *ptr = p;
        status = success;
    }
    return status;
}

Status List_Prior(ListPtr L, int pos, ElemType *elem) {
    Status status = fail;
    ListNodePtr ptr;
    status = List_SetPosition(L, pos - 1, &ptr);
    if (status == success) {
        *elem = ptr->data;
    }
    return status;
}

Status List_Next(ListPtr L, int pos, ElemType *elem) {
    Status status = fail;
    ListNodePtr ptr;
    status = List_SetPosition(L, pos + 1, &ptr);
    if (status == success) {
        *elem = ptr->data;
    }
    return status;
}

Status List_Insert(ListPtr L, int pos, ElemType elem) {
    Status status = fail;
    ListNodePtr ptr, s;
    status = List_SetPosition(L, pos - 1, &ptr);
    if (status == success) {
        s = (ListNodePtr)malloc(sizeof(ListNode));
    }
    if (s) {
        s->data = elem;
        s->next = ptr->next;
        ptr->next = s;
    }
    else {
        status = fail;
    }
    return status;
}

Status List_Remove(ListPtr L, int pos) {
    Status status = fail;
    ListNodePtr ptr;
    status = List_SetPosition(L, pos - 1, &ptr);
    if (status == success) {
        ptr->next = ptr->next->next;
        free(ptr->next);
    }
    return status;
}

Status List_Create(ListPtr L, ElemType elem[], int n) {
    Status status = success;
    ListNodePtr p, q;
    int i = n - 1;
    q = (ListNodePtr)malloc(sizeof(ListNode));
    q->next = NULL;
    while (i >= 0) {
        p = (ListNodePtr)malloc(sizeof(ListNode));
        if (!p) {
            status = fatal;
            break;
        }
        p->data = elem[i];
        p->next = q->next;
        q->next = p;
        i--;
    }
    *L = q;
    return status;
}