.TH cf-demo 1 
.SH NAME 
cf-demo \- demonstration of continued fraction library
.SH SYNOPSIS
        cf-demo e         # calculate decimal expansion of \fIe\fR
        cf-demo \fIx\fR         # calculate expansion of \fIreal\fR
        cf-demo \fIn d\fR       # calculate expansion of \fIn/d\fR
        cf-demo \fIa b c d x\fR # calculate expansion of \fI(ax+b)/(cd+x)\fR
        cf-demo \fIa b c d e f h x y\fR # calculate expansion of \fI(axy+bx+cy+d)/(exy+fx+gy+h)\fR
        cf-demo \fIx\fR + \fIy\fR   # calculate expansion of \fIx\fR + \fIy\fR
        cf-demo \fIx\fR - \fIy\fR   # calculate expansion of \fIx\fR - \fIy\fR
        cf-demo \fIx\fR * \fIy\fR   # calculate expansion of \fIx\fR * \fIy\fR
        cf-demo \fIx\fR / \fIy\fR   # calculate expansion of \fIx\fR / \fIy\fR
        cf-demo '->d' \fIx\fR       # calculate decimal expansion of \fIx\fR

.SH DESCRIPTION

.B cf-demo
is a demonstration program for the 
.BF cf
continued-fraction calculation library. 
.B demo
can be invoked in several ways to exercise the various features of
.BR cf .

.IP \fBdemo\ \fIn\ d\fR
calculates and prints the continued-fraction expansion of the rational
number 
.IR n / d 
where 
.I n 
and 
.I d
are integers.  The
.B cf
function 
.IR new_rat ()
is used to manufacture the continued-fraction object, and then 
.IR print_cf ()
is used to print the terms of the continued fraction.

.IP \fBdemo\ \fIx\fR
uses 
.IR new_rat_from_float ()
to build a continued fraction with the value of 
.IR x ,
which is a floating-point number in the usual format.
The terms of the continued fraction are then printed.

.IP \fBdemo\ \fIa\ b\ c\ d\ x\fR
first uses 
.IR new_rat_from_float ()
to convert 
.I x
to a continued fraction, and then
.IR new_holo ()
to calculate a continued-fraction expansion for the value
.IR ax + b
/
.IR cx + d .
The terms of this latter continued fraction are then printed.
.I x
should be in floating-point format; 
.IR a ,\  b ,\  c ,\ and\  d
should be integers. 

.IP \fBdemo\ \fIa\ b\ c\ d\ e\ f\ g\ h\ x\ y\fR
uses 
.IR new_rat_from_float ()
to convert 
.IR x and y
to continued fractions, and then
.IR new_arith () 
to calculate a continued-fraction expansion for the value
.IR axy + bx + cy + d
/
.IR exy + fx + gy + h .
The terms of this latter continued fraction are then printed.
.I x
and
.I y
should be in floating-point format; 
.IR a ,\  b ,\  c ,\  d ,\  e ,\  f ,\  g ,\ and\  h
should be integers. 

.IP \fBdemo\ \fIx\ \fR+\ \fIy\fR
.IP \fBdemo\ \fIx\ \fR-\ \fIy\fR
.IP \fBdemo\ \fIx\ \fR*\ \fIy\fR
.IP \fBdemo\ \fIx\ \fR/\ \fIy\fR

.I x
and 
.I y
are real numbers in floating-point format.  
.IR new_rat_from_float ()
is called to convert them to continued-fraction representation, and
then  
.IR new_arith () 
is used to perform the indicated operation (addition, subtraction,
multiplication, or division) is performed on the two values.  The
terms of the result then printed.

.P
Note that '*' is special in the shell and will need to be quoted.  The
program will accept the letter "x" as a synonym.

.IP \fBdemo\ \fRe

This calculates and prints the decimal value of \fIe\fR (2.71818...)
from the continued fraction representation.  Specifically, the
continued fraction [2; 1, 2, 1, 1, 4, 1, 1, 6, 1, 1, 8, 1, ...] is
contstructed, and then
.IR new_dec ()
is used to convert it to a decimal.

.IP  \fBdemo\ \fR'->d'\ \fIx\fR

.I x
is a real number as above.  The real number is converted to a
continued fraction, using
.IR new_rat_from_float ().
The continued fraction is then converted back to a sequence of
decimal digits, using
.IR new_dec (), 
and the decimal digits are displayed.

.SH AUTHOR

Mark Jason Dominus (mjd@plover.com)