Quincy 2005: Free Integrated Development Environment for Windows. The latest, easier to install version. Recommended for all Windows versions (Vista needs SP2).
Just follow the wizard to install.
[Download from codecutter.net] [Download from cs.ryerson.ca]

Quincy 99: Free Integrated Development Environment for Windows. Harder to install. Recommended for Windows Vista without SP2 upgrade.
Installation instructions:
1) Download the 8MB zipped file from the Ryerson University server (see link below).
2) Create a new folder named quincy on your computer and extract all the content of the zip file into it. Always create the quincy folder right under the root C:\ drive (or another hard drive if you have one). After extraction you should see inside the quincy folder the quincy application and a folder named mingw32.
3) Start the quincy program by clicking twice on its icon. An error message should appear indicating that you should set compiler paths. Click OK on that dialog and choose the Tools>Compiler paths menu. In the compiler field, write C:\quincy\mingw32\ (change the C to the drive you installed quincy in if necessary), leave the second field blank. Press OK.
4) Start programming! [Download from cs.ryerson.ca]

C-Free: Free Integrated Development Environment for Windows. Easy to install. Works with all Windows versions.
[Download from programarts.com] [Download from cs.ryerson.ca]

FOR PERSONAL COMPUTER USE ONLY - DO NOT DOWNLOAD/INSTALL IN RYERSON LABS

Xcode:
A C integrated development environment for Macintosh made by Apple.