应用c语言双向链实现初始化，生成线性表3 55 2 9 7 32 66，遍历输出线性表并给出表长;将你学号后三位数值插入到第3个位置，遍历输出线性表并给出表长；将第5个元素删除，遍历输出线性表，给出表长和被删除元素；销毁线性表，显示销毁结果

在C语言中，我们可以使用双向链表（Doubly Linked List）来实现线性表的初始化、插入、删除以及遍历操作。这里是一个简单的示例来满足您的需求：

首先，我们创建一个双向链表节点结构体：

typedef struct Node {
    int data;
    struct Node* prev;
    struct Node* next;
} Node;

1. 初始化线性表并遍历输出：

Node* initList(int arr[], int size) {
    Node* head = NULL, *tail = NULL;
    for (int i = 0; i < size; ++i) {
        Node* newNode = malloc(sizeof(Node));
        newNode->data = arr[i];
        newNode->prev = NULL;
        if (head == NULL) {
            head = tail = newNode;
        } else {
            tail->next = newNode;
            newNode->prev = tail;
            tail = newNode;
        }
        printf("%d ", newNode->data);
    }
    printf("\n");
    return head;
}

// 遍历输出
void printList(Node* head) {
    Node* temp = head;
    while (temp != NULL) {
        printf("%d ", temp->data);
        temp = temp->next;
    }
    printf("\n");
}

2. 插入后三位数到第3个位置，并遍历输出：

void insertAfterNode(Node* head, int index, int value) {
    Node* newNode = malloc(sizeof(Node));
    newNode->data = value;
    newNode->prev = head;
    newNode->next = head->next;

    if (index == 0) {
        newNode->next->prev = newNode;
        head = newNode;
    } else {
        Node* current = head->next;
        for (int i = 1; i < index - 1 && current != NULL; i++) {
            current = current->next;
        }
        if (current != NULL) {
            newNode->prev = current->prev;
            newNode->next = current;
            current->prev->next = newNode;
            current->prev = newNode;
        }
    }

    // 输出新表
    printList(head);
}

// 给定例子：学号后三位数值设为123
insertAfterNode(head, 3, 123); 

3. 删除第5个元素，遍历输出并计算表长：

void deleteElement(Node** head, int index) {
    if (*head == NULL) return;

    if (index == 0) {
        Node* temp = *head;
        *head = *head->next;
        free(temp);
    } else {
        Node* current = *head;
        for (int i = 1; i < index && current != NULL; i++) {
            current = current->next;
        }
        if (current != NULL) {
            current->prev->next = current->next;
            if (current->next != NULL) {
                current->next->prev = current->prev;
            }
            free(current);
        }
    }

    // 输出新表
    printList(*head);
    int length = getLength(head);
    printf("表长: %d\n", length);

    // 计算表长辅助函数
    int getLength(Node* head) {
        int count = 0;
        Node* temp = head;
        while (temp != NULL) {
            count++;
            temp = temp->next;
        }
        return count;
    }
}

deleteElement(&head, 4);  // 第5个元素是索引4

4. 销毁线性表（仅释放内存，无实际输出）：

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

destroyList(head);  // 销毁线性表

注意：这个例子假设所有内存分配都能成功，实际情况需要考虑错误处理。此外，`getLength`函数可以合并到`deleteElement`中，以避免不必要的内存访问。