Qt → Qt/C++ - Tutorial 067. Using QMultiMap for a dictionary of synonyms

Qt, QMultiMap, QTableView, QStandardItemModel

QMultiMap is a class inherited from QMap, which allows you to store multiple values for a single key. That is, the key can be repeated. This class can be used, for example, to represent a dictionary of synonyms.

Let's write …

C++ → C++ - Tutorial 004. Tests and loops

C++, while, for, do, break, continue, if, else

C++ provides a standard set of operators for selecting a selection and cycles.

The keywords related to the construction of branching conditions for the code are:

• if
• else
• switch
• case
• break
• default

The key words relating to the construction of …

Qt → Qt/C++ - Tutorial 066. Uploading files to an FTP server

Qt, QNetworkAccessManager, FTP

To work with the network in Qt 5 , the Network module is used, and for data transmission over the network, you can actively use the QNetworkAccessManager class if you do not create your own protocol for data transfer. But …

C++ → C++ - Tutorial 003. Constants

C++, const, constexpr

C =++ supports two notations of immutability:

1. const - which implies that the value will not change. First of all, this is used to specify interfaces, for data that is passed to functions and methods so that they are not …

PostgreSQL → Correcting the client encoding of the PostgreSQL database from LATIN1 to UTF8

PostgreSQL, Django, LATIN1, UTF8

On the site there was one bug that manifested itself when trying to attach to files messages whose names were in Cyrillic. In this case, the site issued error 503. This occurred despite the fact that the database was encoded …

C++ → C++ - Tutorial 002. Types, Variables and Arithmetic

C++, int, char, double, auto, nullptr

Each variable or expression has its own data type, for example, an declaration

int some_variable;

Indicates that the variable some_variable has an integer type int .

The declaration allows you to enter a variable in the program. This variable will …

Django → Django - Tutorial 024. Polling with AJAX

AJAX, Django, Polling

Frequent surveys with AJAX allow you to establish a permanent connection between the browser and the server in order to update any data, for example, whether there are new notifications on the site for the user. For example, I organized …

C++ → C++ - Tutorial 001. Hello World

C++, Hello World

The minimum program in C ++ is

int main() { } // the minimal C++ program

In this program, the declaration of the main function is presented, which takes no arguments. The curly brackets reflect grouping in C++ and in …

Qt → Qt/C++ - Lesson 065. The correspondence of HTTP errors to server response errors in QNetworkAccessManager

QNetworkReply, QNetworkError, QNetworkAccessManager

In one of the lessons, I worked with QNetworkAccessManager to get the content of the page from the site via the http protocol. There was made a check for errors, but no explanation was given as to what errors might …

Qt → Qt/C++ - Lesson 064. How to hide items from the QComboBox drop-down list

Qt, QComboBox, QListView

In some cases, it is required to hide some items from the QComboBox drop-down list. For example, the user is given the opportunity to select one of several options in QComboBox, but by default the invalid option should be displayed, …

Django → Django - Tutorial 023. Like Dislike system using GenericForeignKey

Like, Django, GenericRelation, Dislike, GenericForeignKey

In the article on creating a system of bookmarks on Django, an example was considered with the use of an abstract model for several types of bookmarks, namely for articles and comments on articles. Attention was also drawn to the …

Qt → Qt/C++ - Tutorial 063. Adding windows inside the main application window using QMdiArea

QMdiArea, Qt, QWidget

Many applications, like a photoshop, can open projects (images, texts, etc.) inside windows that open inside the main application window. Qt provides a similar function as QMdiArea . In an object of this class, you can place class objects inherited …