be based on C Language implementation of human-computer interaction software

Task overview

On the basis of data structure theory , Advance complexity 、 Full-featured 、 Programming with friendly interaction , Complete the algorithm realization problem and the comprehensive answer problem respectively .

Overview of content implementation

send C++ Qt The framework completes the graphic performance of the correlation graph algorithm in the algorithm implementation problem .

Make the sound clear UI frame SwiftUI Complete the comprehensive answer ： Subway transfer system .

Algorithm implementation design description

subject

• The formula of adjacency matrix determines a graph , complete ：
• Build and display its adjacent linked list ;
• Traversal with recursion and recursive depth first , Show traversal results , And display the stack at any time 、 situation ;
• First traverse the progress of the graph , Show traversal results , And show the queue at any time 、 situation .

software function

The software function is divided into two parts , Interaction and algorithm functions . Interaction embodies the operation that enables the software to advance from time to time ; The algorithm function reflects the real value of the software . The interaction adopts

C++ Qt frame , Algorithm functions adopt C++14, Make quantity C++ characteristic .

User interaction

First , Software has flexible boundaries , Almost all the visible elements in the painting can be dragged by the user logo , Make the user change the painting according to the demand .

secondly , The software has menu items for users to operate , The cutting operation is in the menu item , There are no more redundant options , So that households almost do not need any learning costs .

Last , There are rich shortcut keys in the menu , Simplify the operation of the software .（ The operation of putting and shrinking can also make Ctrl/Command + The roller goes in , Experience naturally .）

Algorithm function

The software has fulfilled the requirements in function realization , Display the adjacency list corresponding to the directed graph in real time , And completed the depth （ Recursion and recursion ）、 The result of degree first traversal is obvious , At the same time

Fruit and stack 、 Queue information . Animation effects are included in the display process , Render the displayed image in real time .

design idea

The design body of the program is divided into three blocks . First, the design and implementation of the algorithm book , Including all the required internal algorithm implementation , And the internal data structure , It doesn't contain any graphic circles ; The second is the design of graphic display , It represents graphic display , Does not contain any algorithm ; Finally, it's the whole of

close , Realize the synchronization of graphics and internal data structure . The design idea follows a design pattern

（Design Pattern）： MVC（Model View Controller）[1].

Model

Data structure and algorithm model adopt C++ To write , Quanshi C++ Features such as templates

（template）,auto, Range for loop 、C++11 Smart pointer to , The data structure of the basic standard library is as follows std::vector, The data structure of level-1 standard library is as follows std::deque、 std::unordered_set.

Definition of graph , It is a vertex storage Value Template of type value ：

template<typename Value> struct Graph;

The code is easy to understand 、 There are detailed notes , More clear thinking , cut C++ Relevant knowledge can be found in

• Examination 《C++ Primer》[2] And officials [3]. Algorithm design reference 《 Introduction to algorithms 》[4]. The whole model is divided into two pieces ：
• Graph.h： The data structure of graphs ,
• GraphAlgorithms.h： Depth first traversal isometric Algorithm .

The data structure of graph contains all graph operations , Such as adding vertices . Graph algorithm returns traversal results through graph operation 、 The result of each update of the stack or queue , For view display . The result type is SearchResult, Is to define the type , Be able to express the information required by all views ：

struct SearchResult {
    //  It records the subscript order of some traversal .
    std::vector<int> indexOrder;    //  The stack is recorded 、 Real time information of the queue .
    std::vector<std::deque<int>> containerCondition;
};

By subscript order and stack 、 Real time information of the queue , It's easy to return to the view layer for rendering .

View

The view layer makes Qt As a development framework , Mainly transported Qt Of Graphics View

Framework[5], The framework can achieve the combination of components . In the program , The idea of graphic display is combination . Adjacency table is displayed by top-down links about each vertex , In this way, the whole view can be regarded as a combination of many vertex chains , It achieves the effect of building views from to .

Also for stacks and queues , It can be seen as a combination of many vertices , And add a frame .

The advantage of adopting the idea of combination in the whole program lies in the repetition of components , The vertices in the program are 4 In modules, the complex ： The display of the graph 、 The display of adjacency table 、 Ergodic result 、 Real time update of stack or queue . So come , The graph of can be divided into individual parts , Reduce the burden of thinking and writing code .

Controller

The controller is the hub for coordinating views and models , With the controller, the separation and synchronization of view and model can be achieved . Its main task has two points . First, make Qt The classes in the model are encapsulated again , The organization is then provided to the view layer display . The second is the synchronization of model and view , For example, after you choose to clear vertices , The controller is responsible for clearing the vertices of the view layer , At the same time, clear the vertices of the model layer .

void clearGraph() {
    if (isAnimating) {
        QMessageBox::warning(this, " operation failed ", " Please wait for the animation to finish ");
        return;
    }
    model.reset();
    graphObject.reset();
    adjointListGraph.resetFromRaw({});
}

When the user clicks to clear the vertex, the above code triggers . Code into 3 It's about reset,model.reset() Delete all vertices in the model ,

graphObject.reset() Delete the vertices in the display , Update the view , Finally, the code clears the adjacency table view . In this way, the model and view are synchronized .

Logical structure and physical structure

Next we will discuss Model The data structure of the Chinese graph model , About View and Controller The result table of can refer to the source code .

The vertices

template<typename Value> struct Graph<Value>::Vertex {
private:
    friend struct Graph<Value>;
    Value value;
    //  Adjacency list , Circular references are not generated , Automatically destroy with smart pointer ,
    // `std::unordered_set<int>` Represents the subscript of the vertex in the graph instead of the value     std::shared_ptr<std::unordered_set<int>> adjointList;
    // ...
}

Each vertex contains the value it needs to store , This defines it as a template type Value. meanwhile , Because the whole graph adopts the formula of adjacency matrix to store , Every vertex will have a derived adjacency table , Here, the adjacency table is defined as a smart pointer to the ordered set .

The function of the smart pointer is to destroy the variables created in the heap according to the index count [2], Avoid memory leaks . The order set adopts the hash storage formula, so that the element is inserted and deleted only to O(1).（ May refer to cppreference Chinese vs std::unordered_set Introduction to [2]） The function of this set is to store the subscripts of the adjacent vertices in the graph structure .（ See below ）

chart

/// Value should be hashable template<typename Value>
struct Graph {
private:
    // `Graph<Value>::Vertex`, Defined below .
    struct Vertex;
    std::vector<Vertex> vertices;
    //  The mapping of each vertex value to its subscript .
    std::unordered_map<Value, int> valueToIndex;
    // ...
}

Figure is a template type , It can be of any type hashable To instantiate . There are two parts stored . First, the vertex vector[2], It is a linear table stored in sequence , You can dynamically insert and delete elements . Next is an order mapping , It maps from a given vertex value to its position in vector Subscript in , To optimize the direct pass value （ Subscript ） To figure out how to operate （ The operation of this should be based entirely on subscripts ）.

The dynamic array formed by vertices and the adjacency table linked by each vertex , The data structure of a digraph can be a complete table .

Development platform

summary

operating system ：macOS Mojave 10.14.6

Programming language ：C++14

Development framework ：Qt 5.13.0

compiler ：clang-1001.0.46.4

IDE：CLion 2019.2（Build with CMake) Transportation environment the above environment can directly transport executable parts . If the above environment, you may need to recompile the whole project , It needs to be equipped with Qt Environment and holding C++14 And can compile Qt The compiler of the library is as MinGW、Clang. The analysis of the operation results of the system shows that at first I used Qt Creator As a development tool , Its advantage is that the environment is configured , Open to make , And integrated Qt Designer Then the production industry . However, its code improvement and community friendliness are not as good as Jetbrains Developed CLion.CLion The code function of allows me to guess the code function according to the description , During the development process, the frequency of reading files is reduced .

To configure CLion Also only needs CMake Code connection Qt Class library , Defecation . The only thing is not external Qt Designer Waiting will be more annoying , But the overall experience is good .

debugging

There are two kinds of debugging section , One is to view variable information by setting breakpoints , The second is through std::cout、qDebug Statements in CLion Integrated console output .

Version control system

In this development, the version control system Git[6] To save the history of the code . At the same time, make the code hosting platform GitHub Will the whole Git The warehouse is stored in the network platform , Make code “ There are traces to follow ”.

Git There are two , The most traditional way is through Mac Band Terminal, meanwhile CLion It is also integrated. Git And the console can make .