Stdafx.h

"Stdafx.h" is commonly used in computer programming as the name of a file which describes include files (mostly both standard system include files and project specific include files) that are used frequently but are changed infrequently. In a project most files refer to the Stdafx.h file.

Since often near to all files refer to Stdafx.h making small changes in it means the entire project needs to be recompiled and small errors in it cause large errors in the rest of the project.