In the age of plain character line printers it was customary to create simple graphs and even graphics by just using the basic printable characters in some intelligent form. The sine codes plot a graph showing sin(x) and cos(x) for the angles from 0 to 360 degree in steps of 5 degrees.
In the early 70's not all languages had decent support for handling text. FORTRAN 4 or Algol 60 were targeted for handling numeric problems, and doing text handling with them was a bit tricky.
C - sine_cc.c
GCCMVS in the version coming with tk4-
update 08 has a bug in printf.
Printing a very small number with %8.5f can produce output like
0.0000000000004, thus more than 5 after digit characters. This
disrupts the nice formatting. JCC works correctly.
FORTRAN 4 - sine_for.f
FORTRAN 4 has only very rudimentary support for handling of characters.
That's what the code tricks around with 'A' formats and Hollerith constants
like /1H*/ in DATA statements, ancient features not needed in Fortran 77
and later.
The jobs directory contains only one type of jobs for sine named
sine_*.JES
which run the code and produce a nice plot. Not much to benchmark here.
Before laser printers allowed to easily combine text and graphical output in the mid 80's the only way to produce high quality graphics was the usage plotters. In general as slow as cumbersome. To get quick, low quality graphics it was customary to create 'line printer plots'. I got exposed to this in the early 80's when analyzing scientific data with the CERN software package HBOOK. HBOOK was a framework, written in Fortran, which allowed to handle one- and two-dimensional histograms. Creating line printer plots of these histograms was a key functionality, and setting the histograms up such that the output fitted reasonably on printer pages was one of usual concerns when using this package.
Remembering these days lead to adding such a line printer plot as test case, and a graph with two functions is about as simple as one can get it.