Long_hw_02

.vs/ProjectSettings.json

@@ -0,0 +1,3 @@
+{
+  "CurrentProjectSetting": "x64-Debug"
+}

.vs/VSWorkspaceState.json

@@ -0,0 +1,12 @@
+{
+  "OutputFoldersPerTargetSystem": {
+    "\u672C\u5730\u8BA1\u7B97\u673A": [
+      "out\\build\\x64-Debug",
+      "out\\install\\x64-Debug"
+    ]
+  },
+  "ExpandedNodes": [
+    ""
+  ],
+  "PreviewInSolutionExplorer": false
+}

.vs/hw02/v17/DocumentLayout.json

@@ -0,0 +1,12 @@
+{
+  "Version": 1,
+  "WorkspaceRootPath": "D:\\Github_clone\\hw02\\",
+  "Documents": [],
+  "DocumentGroupContainers": [
+    {
+      "Orientation": 0,
+      "VerticalTabListWidth": 256,
+      "DocumentGroups": []
+    }
+  ]
+}

.vscode/tasks.json

@@ -0,0 +1,28 @@
+{
+    "tasks": [
+        {
+            "type": "cppbuild",
+            "label": "C/C++: g++.exe 生成活动文件",
+            "command": "C:\\mingw64\\bin\\g++.exe",
+            "args": [
+                "-fdiagnostics-color=always",
+                "-g",
+                "${file}",
+                "-o",
+                "${fileDirname}\\${fileBasenameNoExtension}.exe"
+            ],
+            "options": {
+                "cwd": "${fileDirname}"
+            },
+            "problemMatcher": [
+                "$gcc"
+            ],
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            },
+            "detail": "调试器生成的任务。"
+        }
+    ],
+    "version": "2.0.0"
+}

main.cpp

@@ -2,93 +2,131 @@
 #include <cstdio>
 #include <memory>
 
-struct Node {
+struct Node
+{
     // 这两个指针会造成什么问题？请修复
-    std::shared_ptr<Node> next;
-    std::shared_ptr<Node> prev;
+    std::unique_ptr<Node> next;
+    Node *prev;
     // 如果能改成 unique_ptr 就更好了!
 
     int value;
 
     // 这个构造函数有什么可以改进的？
-    Node(int val) {
-        value = val;
-    }
+    Node(const int &val) : value(val) {}
 
-    void insert(int val) {
-        auto node = std::make_shared<Node>(val);
-        node->next = next;
+    void insert(int val)
+    {
+        auto node = std::make_unique<Node>(val);
+        if (next)
+        {
+            next->prev = node.get();
+        }
+        node->next = std::move(next);
         node->prev = prev;
         if (prev)
-            prev->next = node;
-        if (next)
-            next->prev = node;
+            prev->next = std::move(node);
     }
 
-    void erase() {
-        if (prev)
-            prev->next = next;
+    void erase()
+    {
         if (next)
+        {
             next->prev = prev;
+        }
+        if (prev)
+        {
+            prev->next = std::move(next);
+        }
     }
 
-    ~Node() {
-        printf("~Node()\n");   // 应输出多少次？为什么少了？
+    ~Node()
+    {
+        printf("~Node()\n"); // 应输出多少次？为什么少了？
     }
 };
 
-struct List {
-    std::shared_ptr<Node> head;
+struct List
+{
+    std::unique_ptr<Node> head;
 
     List() = default;
 
-    List(List const &other) {
-        printf("List 被拷贝！\n");
-        head = other.head;  // 这是浅拷贝！
+    List(List const &other)
+    {
+        auto head = std::make_unique<Node>(other.head->value);
+
+        if (!other.head)
+        {
+            head = nullptr;
+        }
+        else
+        {
+            auto ptr_this = head.get();
+            auto ptr_other = other.head.get();
+            while (ptr_other->next)
+            {
+                ptr_this->next = std::make_unique<Node>(ptr_other->next->value);
+                ptr_this->next->prev = ptr_this;
+                ptr_other = ptr_other->next.get();
+                ptr_this = ptr_this->next.get();
+            }
+        }
+        // 这是浅拷贝！
         // 请实现拷贝构造函数为 **深拷贝**
     }
 
-    List &operator=(List const &) = delete;  // 为什么删除拷贝赋值函数也不出错？
+    List &operator=(List const &) = delete; // 为什么删除拷贝赋值函数也不出错？
 
     List(List &&) = default;
     List &operator=(List &&) = default;
 
-    Node *front() const {
+    Node *front() const
+    {
         return head.get();
     }
 
-    int pop_front() {
+    int pop_front()
+    {
         int ret = head->value;
-        head = head->next;
+        head = std::move(head->next);
         return ret;
     }
 
-    void push_front(int value) {
-        auto node = std::make_shared<Node>(value);
-        node->next = head;
+    void push_front(int value)
+    {
+        auto node = std::make_unique<Node>(value);
         if (head)
-            head->prev = node;
-        head = node;
+        {
+            head->prev = node.get();
+        }
+        node->next = std::move(head);
+
+        head = std::move(node);
     }
 
-    Node *at(size_t index) const {
+    Node *at(size_t index) const
+    {
         auto curr = front();
-        for (size_t i = 0; i < index; i++) {
+        for (size_t i = 0; i < index; i++)
+        {
             curr = curr->next.get();
         }
         return curr;
     }
 };
 
-void print(List lst) {  // 有什么值得改进的？
+void print(List const &lst)
+{ // 有什么值得改进的？
     printf("[");
-    for (auto curr = lst.front(); curr; curr = curr->next.get()) {
+    for (auto curr = lst.front(); curr; curr = curr->next.get())
+    {
         printf(" %d", curr->value);
     }
     printf(" ]\n");
 }
 
-int main() {
+int main()
+{
     List a;
 
     a.push_front(7);
@@ -99,18 +137,19 @@ int main() {
     a.push_front(4);
     a.push_front(1);
 
-    print(a);   // [ 1 4 9 2 8 5 7 ]
+    print(a); // [ 1 4 9 2 8 5 7 ]
 
     a.at(2)->erase();
+    a.at(2)->insert(9);
 
-    print(a);   // [ 1 4 2 8 5 7 ]
+    print(a); // [ 1 4 2 8 5 7 ]
 
     List b = a;
 
     a.at(3)->erase();
 
-    print(a);   // [ 1 4 2 5 7 ]
-    print(b);   // [ 1 4 2 8 5 7 ]
+    print(a); // [ 1 4 2 5 7 ]
+    print(b); // [ 1 4 2 8 5 7 ]
 
     b = {};
     a = {};