c++链表基本操作

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

typedef struct Node
{
    int data;
    struct Node *pNext;
}NODE,*PNODE;

PNODE create_list(void);
void traverse_list(PNODE);
bool is_empty(PNODE pHead);
int length_list(PNODE);
bool insert_list(PNODE, int, int);
bool delete_list(PNODE,int,int*);
void sort_list(PNODE);

int main(void)
{
    PNODE pHead = NULL;
    int val;
    pHead = create_list();
    sort_list(pHead);
    if (delete_list(pHead, 4, &val))
    {
        printf("delete %d ok!
",val);
    }
    else
    {
        printf("delete wrong");
    }
    traverse_list(pHead);
    int len = length_list(pHead);
    if (is_empty(pHead))
    {
        printf("list is empty!");
    }
    else
    {
        printf("list isn't empty！");
    }
    return 0;
}

PNODE create_list(void)
{
    int len;
    int val;//用于存放用户输入的结点的值
    printf("请输入链表的长度：len=");
    scanf("%d", &len);
    PNODE pHead = (PNODE)malloc(sizeof(Node));

    if (NULL == pHead)
    {
        printf("分配失败，程序终止!");
        exit(-1);
    }
    PNODE pTail = pHead;
    pTail->pNext = NULL;

    for (int i = 0; i < len; ++i)
    {
        printf("请输入第%d个节点的值", i + 1);
        scanf("%d", &val);
        PNODE pNew = (PNODE)malloc(sizeof(Node));
        if (NULL == pNew)
        {
            printf("分配失败，程序终止!");
            exit(-1);
        }
        pNew->data = val;
        pTail->pNext = pNew;
        pNew->pNext = NULL;
        pTail = pNew;
    }
    return pHead;
}

void traverse_list(PNODE pHead)
{
    PNODE p = pHead->pNext;
    while (NULL != p)
    {
        printf("%d", p->data);
        p = p->pNext;
    }
    printf("
");
}

bool is_empty(PNODE pHead)
{
    if (NULL == pHead->pNext)
    {
        return true;
    }
    return false;
}

int length_list(PNODE pHead)
{
    int length = 0;
    PNODE p = pHead->pNext;
    while (NULL != p)
    {
        length++;
        p = p->pNext;
    }
    return length;
}

void sort_list(PNODE pHead)
{
    int i, j, t;
    int len = length_list(pHead);
    PNODE p, q;
    for (i = 0, p = pHead->pNext; i < len - 1; ++i, p=p->pNext)
    {
        for (j = i + 1, q = p->pNext; j < len; ++j, q = q->pNext)
        {
            if (p->data > q->data)
            {
                t = p->data;
                p->data = q->data;
                q->data = t;
            }
        }
    }
    return;
}
//在pHead指向链表的第pos个节点的前面插入一个新的节点，该节点的值为value,pos从1开始
bool insert_list(PNODE pHead, int pos, int value)
{
    int i = 0;
    PNODE p = pHead;
    while (NULL != p && i < pos - 1)
    {
        p = p->pNext;
        ++i;
    }
    if (i > pos - 1 || NULL == p)
        return false;
    PNODE pNew = (PNODE)malloc(sizeof(NODE));
    if (NULL == pNew)
    {
        printf("动态分配内存失败！
");
        exit(-1);
    }
    pNew->data = value;
    PNODE q = p->pNext;
    p->pNext = pNew;
    pNew->pNext = q;
    return true;
}

bool delete_list(PNODE pHead, int pos, int *pVal)
{
    int i = 0;
    PNODE p = pHead;
    while (NULL != p->pNext && i < pos - 1)
    {
        p = p->pNext;
        ++i;
    }
    if (i > pos - 1 || NULL == p->pNext)
    {
        return false;
    }
    PNODE q = p->pNext;
    *pVal = q->data;
    //删除p节点后面的节点
    p->pNext = p->pNext->pNext;
    free(q);
    q = NULL;
    return true;
}


/*
1.链表的删除，比如删除p后的节点，如何操作？有时很容易遗漏free(r)的操作，导致内存泄漏。
可以如下操作：
r = p->next;
p->next = r->next;
free(r);
*/