GradeTrain is an automated grading, instant feedback platform, and preconfigured coding environment for computer programming courses. In the IDE students can program directly online, without the need to download anything. The time consuming process of grading and giving high level feedback on programming projects is automated, which allows students to learn from their mistakes and become better programmers without having to wait for feedback from their professors. The platform also makes it simple to manage a class.
The online IDE works with MATLAB, C++, Java, Ruby, and Python. It provides hints for errors by giving possible causes.
You can try it at www.gradetrain.com