在单链表中存储信息结构

Question

我正在尝试将人员信息结构存储到单个链表中并对其执行一些操作

我的结构信息是

struct Person {
    char name[MAX];
    char id[MAX];
};

而我的单链表是使用 struct like

定义的

struct Node {
    struct Person* pPerson;
    struct Node* pNext;
};

我的想法是通过获取用户

的输入来定义一个Person结构

struct Person* newPerson() {
    Person* pPerson = NULL;
    pPerson = (Person*)malloc(sizeof(Person));
    printf("name: "); scanf("%s", pPerson->name);
    printf("id: "); scanf("%s", pPerson->id);
    
    return pPerson;
}

这是initNode新创建节点的功能

struct Node* newNode(Person* pNewPerson) {
    Node* pPeople = NULL;
    pPeople = (struct Node*)malloc(sizeof(struct Node));
    pPeople->pPerson = pNewPerson;
    return pPeople;
}

这是我的 insert 函数，它在列表中存储 struct Person

void insert(Node* pHead, Person* pNewPerson) {
    Node* pCurrent = pHead;
    while (pCurrent != NULL) {
        pCurrent = pCurrent->pNext;
    }
    
    pCurrent = (Node*)malloc(sizeof(Node));
    pCurrent->pNext->pPerson = pNewPerson;
    pCurrent->pNext = NULL;
}

最后是display函数

void display(Node* pHead) {
    Node* pCurrent = pHead;
    int index = 1;
    
    while (pCurrent != NULL) {
        printf("Person %d\n", index);
        printf("name: %s\n", pCurrent->pPerson->name);
        printf("id: %s\n", pCurrent->pPerson->id);
        index += 1;
        pCurrent = pCurrent->pNext;
    }
}

我只是测试，但我的代码中某处似乎有误

    Node* pNode = NULL;
    Person* pPerson = NULL;
    pPerson = newPerson();
    pNode = newNode(pPerson);
    insert(pNode, pPerson);
    display(pNode);

当我得到输入值但输出是 segmentation default core dump。我是指针的新手，我只是按照逻辑将指针分配到需要的位置。

有人可以纠正我吗？

EDIT: 问题已解决

struct Person* newPerson() {
    Person* pPerson = NULL;
    pPerson = (Person*)malloc(sizeof(Person));
    printf("name: "); scanf("%s", pPerson->name);
    printf("id: "); scanf("%s", pPerson->id);
    
    return pPerson;
}

struct Node* newNode(Person* pNewPerson) {
    Node* pPeople = (struct Node*)malloc(sizeof(struct Node));
    pPeople->pPerson = pNewPerson;
    pPeople->pNext = NULL;
    return pPeople;
}

void insert(Node* pHead, Person* pNewPerson) {
    Node* pCurrent = pHead;
    if (pCurrent == NULL)
    {
        return pNewNode;
    }
    while (pCurrent-> pNext != NULL) {
        pCurrent = pCurrent->pNext;
    }
    pCurrent->pNext = pNewNode;
}

void display(Node* pHead) {
    Node* pCurrent = pHead;
    int index = 1;
    
    while (pCurrent != NULL) {
        printf("Person %d\n", index);
        printf("name: %s\n", pCurrent->pPerson->name);
        printf("id: %s\n", pCurrent->pPerson->id);
        index += 1;
        pCurrent = pCurrent->pNext;
    }
}

Answer 1

在您的 insert 函数中，您访问 pCurrent->pNext，但是 pNext 未由 newNode 初始化。

Answer 2

您的 insert 函数有几个错误。

简短的回答是：

Node* insert(Node* pHead, Node* pNewNode) {
    Node* pCurrent = pHead;
    if (pCurrent == NULL)
    {
        return pNewNode;
    }
    while (pCurrent->next != NULL) {
        pCurrent = pCurrent->pNext;
    }
    pCurrent->pNext = pNewNode;
    return pHead;
}

并这样称呼它：

Node* pHead = NULL;
Person* pPerson = newPerson();
Node* pNewNode = newNode(pPerson);
pHead = insert(pHead, pNewNode);

并在 newNode 函数中插入 pPeople->pNext = NULL;。

解释：

从这里开始：

void insert(Node* pHead, Person* pNewPerson) {

为什么要以pNewPerson为参数？您已经使用 newNode 函数将新人插入到节点中。所以改为：

void insert(Node* pHead, Node* pNewNode) {
    ...
}

并这样称呼它：

Node* pHead = NULL;
Person* pPerson = newPerson();
Node* pNewNode = newNode(pPerson);
insert(pHead, pNewNode);

这部分：

while (pCurrent != NULL) {
    pCurrent = pCurrent->pNext;
}

让您越过最后一个元素，因此您无法将新元素添加到最后一个元素。您的代码应该是：

void insert(Node* pHead, Node* pNewNode) {
    Node* pCurrent = pHead;
    if (pCurrent == NULL)
    {
        ..se later..
    }
    while (pCurrent->next != NULL) {
        pCurrent = pCurrent->pNext;
    }
    // Now pCurrent points to the last element

您插入元素的代码也有误 - 请参阅评论

pCurrent = (Node*)malloc(sizeof(Node));  // Why malloc - you did that in newNode-function
pCurrent->pNext->pPerson = pNewPerson;   // Why - you did that in newNode-function
pCurrent->pNext = NULL;

大部分代码都不需要。只要做：

void insert(Node* pHead, Node* pNewNode) {
    Node* pCurrent = pHead;
    if (pCurrent == NULL)
    {
        ..se later..
    }
    while (pCurrent->next != NULL) {
        pCurrent = pCurrent->pNext;
    }
    pCurrent->pNext = pNewNode;
}

现在如果 pHead 为 NULL 怎么办？在这种情况下，您需要将 pHead 更新为新节点。为此，您需要再次更改功能。一种方式是：

Node* insert(Node* pHead, Node* pNewNode) {
    Node* pCurrent = pHead;
    if (pCurrent == NULL)
    {
        return pNewNode;
    }
    while (pCurrent->next != NULL) {
        pCurrent = pCurrent->pNext;
    }
    pCurrent->pNext = pNewNode;
    return pHead;
}

并这样称呼它：

Node* pHead = NULL;
Person* pPerson = newPerson();
Node* pNewNode = newNode(pPerson);
pHead = insert(pHead, pNewNode);

Answer 3

你可以像下面这样改变插入函数的while循环。

   while (pCurrent != NULL && pCurrent->pNext != NULL) {
        pCurrent = pCurrent->pNext;
    }

您收到分段错误的原因是当 pCurrent->pNext 为 Null 时，您将空值设置为 pCurrent 指针。之后，您尝试在以下代码中取消引用空指针；

pCurrent->pNext = malloc(sizeof(struct Node));

您还可以查看@4386427 的回答和解释，我没有查看您代码的其他部分，但由于我在上面指定的原因，您收到了分段错误。

在单链表中存储信息结构

store struct of info in single linked list

c

struct

pointers

singly-linked-list