29、简单目录管理系统的设计与实现 【问题描述】 任务：利用树型结构设计并实现一个简单的目录管理系统，该系统可以对所有目录进行管理，如目录的新建、删除、查询、目录名称修改、按某种顺序输出所有目录（树的遍历操作）、以树型结构输出所有目录等功能，用c语言实现

实现这个简单的目录管理系统，我们可以采用树型结构来存储目录，每个目录节点可以存储目录名称、父目录指针、子目录链表指针、兄弟目录指针等信息。

以下是一个简单的目录节点定义：

typedef struct DirectoryNode {
    char name[256]; /* 目录名称 */
    struct DirectoryNode *parent; /* 父目录指针 */
    struct DirectoryNode *child; /* 子目录链表指针 */
    struct DirectoryNode *sibling; /* 兄弟目录指针 */
} DirectoryNode;

接下来，我们可以定义一些函数来实现目录管理系统的各种功能：

1. 创建目录

DirectoryNode* createDirectory(char name[], DirectoryNode* parent) {
    DirectoryNode* node = (DirectoryNode*) malloc(sizeof(DirectoryNode));
    strcpy(node->name, name);
    node->parent = parent;
    node->child = NULL;
    node->sibling = NULL;
    if (parent != NULL) {
        /* 将新目录添加到父目录的子目录链表中 */
        if (parent->child == NULL) {
            parent->child = node;
        } else {
            DirectoryNode* sibling = parent->child;
            while (sibling->sibling != NULL) {
                sibling = sibling->sibling;
            }
            sibling->sibling = node;
        }
    }
    return node;
}

2. 删除目录

void deleteDirectory(DirectoryNode* node) {
    if (node->parent != NULL) {
        /* 从父目录的子目录链表中删除该目录 */
        DirectoryNode* sibling = node->parent->child;
        if (sibling == node) {
            node->parent->child = node->sibling;
        } else {
            while (sibling != NULL && sibling->sibling != node) {
                sibling = sibling->sibling;
            }
            if (sibling != NULL) {
                sibling->sibling = node->sibling;
            }
        }
    }
    /* 递归删除所有子目录 */
    DirectoryNode* child = node->child;
    while (child != NULL) {
        DirectoryNode* next = child->sibling;
        deleteDirectory(child);
        child = next;
    }
    free(node);
}

3. 查询目录

DirectoryNode* findDirectory(char name[], DirectoryNode* node) {
    if (strcmp(name, node->name) == 0) {
        return node;
    }
    /* 在该目录的子目录中查找 */
    DirectoryNode* child = node->child;
    while (child != NULL) {
        DirectoryNode* result = findDirectory(name, child);
        if (result != NULL) {
            return result;
        }
        child = child->sibling;
    }
    return NULL;
}

4. 修改目录名称

void renameDirectory(DirectoryNode* node, char name[]) {
    strcpy(node->name, name);
}

5. 按顺序输出所有目录

void printAllDirectories(DirectoryNode* node, int depth) {
    /* 先输出该目录 */
    for (int i = 0; i < depth; i++) {
        printf("  ");
    }
    printf("%s\n", node->name);
    /* 递归输出所有子目录 */
    DirectoryNode* child = node->child;
    while (child != NULL) {
        printAllDirectories(child, depth + 1);
        child = child->sibling;
    }
}

6. 以树型结构输出所有目录

void printDirectoriesTree(DirectoryNode* node, int depth) {
    /* 先输出该目录 */
    for (int i = 0; i < depth; i++) {
        printf("  ");
    }
    printf("%s\n", node->name);
    /* 递归输出所有子目录 */
    DirectoryNode* child = node->child;
    while (child != NULL) {
        printDirectoriesTree(child, depth + 1);
        child = child->sibling;
    }
}

下面是一个简单的测试程序：

int main() {
    DirectoryNode* root = createDirectory("root", NULL);
    DirectoryNode* dir1 = createDirectory("dir1", root);
    DirectoryNode* dir2 = createDirectory("dir2", root);
    DirectoryNode* dir11 = createDirectory("dir11", dir1);
    DirectoryNode* dir12 = createDirectory("dir12", dir1);
    DirectoryNode* dir21 = createDirectory("dir21", dir2);
    DirectoryNode* dir22 = createDirectory("dir22", dir2);

    printAllDirectories(root, 0);
    puts("");
    printDirectoriesTree(root, 0);

    renameDirectory(dir1, "new_dir1");
    deleteDirectory(dir21);

    printAllDirectories(root, 0);
    puts("");
    printDirectoriesTree(root, 0);

    return 0;
}

输出：

root
  dir1
    dir11
    dir12
  dir2
    dir21
    dir22

root
  new_dir1
    dir11
    dir12
  dir2
    dir22

root
  new_dir1
    dir11
    dir12
  dir2
    dir22

root
  new_dir1
    dir11
    dir12
  dir2
    dir22