wxWidgets - wxWidgets: Cross-Platform GUI Library
Orwell Dev-C - The official site of the Bloodshed Dev-C++ update, which is fully portable, and optionally ships with a 64bit compiler.
Electron - Build cross platform desktop apps with web technologies
Netbeans - NetBeans IDE 7.0. Develop desktop, mobile and web applications with Java, PHP, C/C++ and more. Runs on Windows, Linux, Mac OS X and Solaris. NetBeans IDE is open-source and free.
GTK - GTK+ is a multi-platform toolkit for creating graphical user interfaces.
CppDroid - CppDroid is simple C/C++ IDE focused on learning programming languages and libraries. Features: