OnlineGDB.com is an online compiler and debugger tool for C/C++ languages. It is world's first online IDE which gives debugging facility with embedded gdb debugger. This is a very handy webapp for coders who love coding in online IDE but face unexpected crashes and tricky bugs in their code. OnlineGDB provides debugging power to such users to help them out.
So all in all, its a great online IDE powered with code editor, compiler and debugger.
Here is short demo to get you started.