QOnlineTranslator is a library for Qt5 that provides free usage of Google, Yandex, Bing, LibreTranslate and Lingva translate API.

Example:

QCoreApplication app(argc, argv);

QOnlineTranslator translator;
translator.translate("Hello world", QOnlineTranslator::Google);
QObject::connect(&translator, &QOnlineTranslator::finished, [&] {
    if (translator.error() == QOnlineTranslator::NoError)
        qInfo() << translator.translation();
    else
        qCritical() << translator.errorString();
});

return QCoreApplication::exec();

For real example of usage you can look into my other project: Crow Translate.

Linux: GCC 7

Windows: MSVC2017 / MinGW 7

To include the library files you could use FetchContent CMake module. Or you can add it as a git submodule to your project and include it's contents:

QMake:

include(src/third-party/qonlinetranslator/qonlinetranslator.pri)

CMake:

add_subdirectory(src/third-party/qonlinetranslator)