Screen IO
Volume Number: 9
Issue Number: 2
Column Tag: C Workshop
Three Subclasses for Screen Input/Output 
Using existing TCL classes to solve the input/output problem
By Gerry H. Kenner, Magna, Utah
Note: Source code files accompanying article are located on MacTech CD-ROM orsource code disks.
About the author
Gerry Kenner is a professional electrical and computer engineering consultant,
university re searcher and sometimes writer who specializes in image analysis
systems for investigative scientists.
INTRODUCTION
While writing and debugging major commercial applications with THINK C 5.0, I
have often needed to input test variables into the program or to do data printouts or
bitmap dumps. In the DOS world the first two can be done fairly easily using printf
and scanf library functions. Likewise, the cin and cout instructions used in C++
provide that language with considerable operational ease.
The third operation is more difficult to perform because it involves dumping the
contents of bitmaps which have been drawn offscreen as well as others in which the