C语言实现线性单链表的定义、初始化、插入、删除及数据的显示、求长度、逆置以及两个有序单链表的合并

在C语言中，线性单链表是一种基础的数据结构，它由节点组成，每个节点包含一个数据域和一个指向下一个节点的指针。下面是定义、初始化、操作和合并的一个简要概述：

**定义与初始化：**

// 定义链表节点结构体
typedef struct Node {
    int data;       // 数据域
    struct Node* next; // 指向下一个节点的指针
} Node;

// 初始化空链表
Node* createList() {
    return NULL;
}

**插入操作：**
- 插入到头部 (`push`):

void push(Node** head, int value) {
    Node* newNode = (Node*)malloc(sizeof(Node));
    newNode->data = value;
    newNode->next = *head;
    *head = newNode;
}

- 插入到尾部 (`append`):

void append(Node** head, int value) {
    if (*head == NULL) {
        push(head, value);
    } else {
        Node* current = *head;
        while (current->next != NULL) {
            current = current->next;
        }
        current->next = (Node*)malloc(sizeof(Node));
        current->next->data = value;
        current->next->next = NULL;
    }
}

**删除操作：**
- 删除首节点 (`deleteFirst`):

void deleteFirst(Node** head) {
    if (*head != NULL) {
        Node* temp = *head;
        *head = (*head)->next;
        free(temp);
    }
}

- 删除指定值的节点 (`deleteByValue`):

void deleteByValue(Node** head, int value) {
    if (*head != NULL && (*head)->data == value) {
        Node* temp = *head;
        *head = (*head)->next;
        free(temp);
    } else {
        Node* current = *head;
        while (current->next != NULL && current->next->data != value) {
            current = current->next;
        }
        if (current->next != NULL) {
            Node* toDelete = current->next;
            current->next = current->next->next;
            free(toDelete);
        }
    }
}

**数据显示：**

void display(Node* head) {
    Node* current = head;
    while (current != NULL) {
        printf("%d -> ", current->data);
        current = current->next;
    }
    printf("NULL\n");
}

**求链表长度：**

int length(Node* head) {
int count = 0;
while (head != NULL) {
count++;
head = head->next;
}
return count;
}

**逆置链表：**

void reverse(Node** head) {
Node* prev = NULL;
Node* current = *head;
Node* nextTemp;
while (current != NULL) {
nextTemp = current->next;
current->next = prev;
prev = current;
current = nextTemp;
}
*head = prev;
}

**合并两个有序链表：**

Node* mergeSortedLists(Node* list1, Node* list2) {
if (list1 == NULL) return list2;
if (list2 == NULL) return list1;

if (list1->data < list2->data) {
list1->next = mergeSortedLists(list1->next, list2);
return list1;
} else {
list2->next = mergeSortedLists(list1, list2->next);
return list2;
}
}