Xamarin Studio!

Microsoft Visual Studio is an integrated development environment (IDE) from Microsoft. It is used to develop computer programs for Microsoft Windows, as well as web sites, web applications and web services. Visual Studio uses Microsoft software development platforms such as Windows API, Windows Forms, Windows Presentation Foundation, Windows Store and Microsoft Silverlight. It can produce both native code and managed code.

A free, open-source Integrated Development Environment for software developers. You get all the tools you need to create professional desktop, enterprise, web, and mobile applications with the Java language, C/C++, and even dynamic languages such as PHP, JavaScript, Groovy, and Ruby. NetBeans IDE is easy to install and use straight out of the box and runs on many platforms including Windows, Linux, Mac OS X and Solaris.The download section conveniently offers prepackaged bundles/installers for each supported programming language containing only required plugins. »

Android Studio is a new Android development environment based on IntelliJ IDEA. Similar to Eclipse with Android Development Tools for Eclipse, Android Studio provides integrated Android developer tools for development and debugging.Best IDE available for Android development specially with limited hardware options on development device.

Code::Blocks is a free C++ IDE built to meet the most demanding needs of its users. It is designed to be very extensible and fully configurable.

Aptana Studio is a complete web development environment that combines powerful authoring tools with a collection of online hosting and collaboration services that help you and your team do more. Includes support for PHP, CSS, FTP, and more...

Qt Creator is a cross-platform C++, JavaScript and QML integrated development environment which is part of the SDK for the Qt Framework.

PhoneGap is an open source development tool for building iPhone, Android, Blackberry and other mobile apps with JavaScript.

Free Pascal is a GPL'ed compiler that runs on Linux, Win32, OS/2, 68K and more. Free Pascal is designed to be able to understand and compile Delphi syntax, which is of course OOP. Lazarus is the part of the missing puzzle that will allow you to develop Delphi like programs in all of the above platforms. Unlike Java which strives to be a write once run anywhere, Lazarus and Free Pascal strives for write once compile anywhere. Since the exact same compiler is available on all of the above platforms it means you don't need to do any recoding to produce identical products for different platforms. »

If you can build a website, you can build a desktop app. Electron is a framework for creating native applications with web technologies like JavaScript, HTML, and CSS. It takes care of the hard parts so you can focus on the core of your application.

Xcode is Apple's premiere development environment for Mac OS X. In addition to being packaged on the DVD with every copy of Mac OS X, the latest Xcode developer release is always available for free to ADC members and includes all the tools you need to create, debug, and optimize your applications. At the heart of the Xcode tools package is the Xcode IDE, a graphical workbench that tightly integrates a professional text editor, a robust build system, a debugger, and the powerful GCC compiler capable of targeting Intel and PowerPC regardless of host platform. Xcode is both easy to use, and yet powerful enough to build the largest Mac OS X applications. The complete Mac OS X developer tools chain is distributed as part of Xcode; these tools include Interface Builder, Instruments, Dashcode, the WebObjects framework, and the complete reference documentation, to name just a few. »

Apache Cordova is a set of device APIs that allow a mobile app developer to access native device function such as the camera or accelerometer from JavaScript. Combined with a UI framework such as jQuery Mobile or Dojo Mobile or Sencha Touch, this allows a smartphone app to be developed with just HTML, CSS, and JavaScript.

CodeLite is an open-source, cross platform IDE for the C/C++/PHP and Node.js programming languages. CodeLite is known to work on various OSs including:

KDevelop is a free, open source IDE (Integrated Development Environment) for Linux, Windows (beta) and macOS (experimental).It is a feature-full, plugin extensible IDE for C/C++, Python, JavaScript and PHP.It is based on KDevPlatform, and the KDE and Qt libraries.

Bloodshed Dev-C++ is a full-featured Integrated Development Environment (IDE) for the C/C++ programming language. It uses Mingw port of GCC (GNU Compiler Collection) as it's compiler. Dev-C++ can also be used in combination with Cygwin or any other GCC based compiler.