Creating a simple Qt application without using Qt Creator or CMake involves writing the necessary code and configuration files manually. Here's a step-by-step guide to create a basic Qt application using just a text editor and the command line:

Step 1: Install Qt

Ensure you have Qt installed on your system. You can download it from the official Qt website.

Step 2: Create Project Structure

Create a directory for your project and navigate into it. Inside this directory, create the following files:

• main.cpp
• project.pro

Step 3: Write the Code

main.cpp

This file will contain the main application code. Here's a simple example of a Qt application that displays a window with a button:

cpp
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#include <QApplication>
#include <QPushButton>

int main(int argc, char *argv[]) {
    QApplication app(argc, argv);

    QPushButton button("Hello, World!");
    button.resize(200, 100);
    button.show();

    return app.exec();
}

project.pro

This file is the project file that qmake uses to generate a Makefile. Here's a simple example:

pro
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QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = simple_qt_app
TEMPLATE = app

SOURCES += main.cpp

Step 4: Build the Project

1. Open a terminal and navigate to your project directory.
2. Run qmake to generate the Makefile:

   bash
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   qmake -project
   qmake

3. Build the project using make:

   bash
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   make

Step 5: Run the Application

After building the project, you can run the application using:

bash
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./simple_qt_app

This will launch a simple Qt application with a window containing a button that says "Hello, World!".

Notes

• Ensure that the Qt binaries are in your system's PATH so that you can run qmake and make from the command line.
• This example assumes you are on a Unix-like system. If you are on Windows, you might need to use nmake instead of make.

This setup allows you to create and build a simple Qt application without relying on Qt Creator or CMake.