To turn in assignments, you will use the handin program on vogon. You will turn your solution in by running the handin command and specifying the files that you want submitted. It should work for you to type the following at the command-line on vogon:

handin mhaungs <dir> <your files>

Where <dir> is the name of the directory in which you are submitting your files and <your files> is the list of files that you presently wish to turn in (e.g., execute.c). You can run handin multiple times (though you should not do so after the deadline), but each subsequent handin will overwrite the files from the previous handin. As such, be certain that you are submitting the files that you want graded. And be certain that you submit all of the files necessary for your program. You can use the above handin command without any files to see which files you have submitted.