For some reason I decided to rewrite the "wave" program that I wrote in Basic-11, but using DECUS C.  I thought that it would be easy, but I didn't count on there not being a math.h.  This means that I had to work out how to calculate a sine and cosine for myself.  Well, actually I went off to google to see if somebody had already done the hard work for me.  Indeed they had, I found it here: www.bsdlover.cn/study/unixtree/V7/usr/src/libm/sin.c.html

That code was already in K&R syntax, but it used modf(), I think that I went off and found some source code for that somewhere else...  Anyway, when I had it working, I decided that I might want to use these bits of maths code somewhere else - so I extracted it out into my own library and made "maths.h".  So I can now use sin/cos wherever I want.

Anyway, since I went to all that trouble, I thought that I had better post the results.  You need to compile maths.c into maths.obj, like this:

.CC
CC> MATHS.C/A
RUN C:AS DK:MATHS.S/D

Then, you can #include "maths.h" and link to the maths.obj we created above, like this example:

LINK WAVE.OBJ,MATHS.OBJ,C:SUPORT.OBJ,C:CLIB.OBJ

I expect I'll add more to my maths library as I go, but this is a start.