The code listings had a comment (rem) at the end of each line with a checksum number, when you used the checksum program it would display a checksum at the top of the screen that would match if you entered the line correctly.
An example page of code with checksums is at https://archive.org/details/1983-10-computegazette/page/146/....
A life changing event for those of us entering code from magazine listings in the early '80s.
The code listings had a comment (rem) at the end of each line with a checksum number, when you used the checksum program it would display a checksum at the top of the screen that would match if you entered the line correctly.
An example page of code with checksums is at https://archive.org/details/1983-10-computegazette/page/146/....
A life changing event for those of us entering code from magazine listings in the early '80s.