Ok, bit by bit :

y=f(x) is the curve.

In our case, f is sin(), y is iSinValue, which makes x = count*PI.

What's not clear?

if you work on unix/linux, check the man page for getopt() function. It helps very much. At first it seems like an overhead, but in fact is very usefull.

Ok, I'll just give you a hint, try to do the program by yourself. Start with matching the characters on the opposite end of the string. On the first mismatch, get the rest of the string, create the...