If you messed up in the code editor, get stuck in a problem, or for any reason you would like to start from scratch on a particular problem, you can click on the reset button 
on the editor toolbar above the code editor to reset your code.
If you messed up in the code editor, get stuck in a problem, or for any reason you would like to start from scratch on a particular problem, you can click on the reset button on the editor toolbar above the code editor to reset your code.