Graphics Programs Reference
In-Depth Information
33 !
36 $
39 '
42 *
45 -
48 0
34 "
37 %
40 (
43 +
46 .
49 1
35 #
38 &
41 )
44 ,
47 /
50 2
Typing
char(7)
rings the bell.
Exercise 9 (Page 80)
The
strvcat
function is used instead of
char
because it ignores empty
strings in the input; the
char
function doesn't:
>> char('','The','','quick')
ans =
The
quick
>> strvcat('','The','','quick')
ans =
The
quick
If
char
were used instead of
strvcat
, the result would always begin with
a blank line.
Exercise 10 (Page 83)
The problem is to deal with the two cases: (1) where the name of a
function or m-file is given, such as '
sin
', and (2) where the function itself
is given, such as '
sin(x)
'. The difference here boils down to whether
the string input contains brackets or not (see hint). In other cases the
string input might not contain brackets, but would contain characters
used in defining a function, such as
+
,
-
,
*
,
/
,or
.
(as in
t.^2
). The
ascii values for these characters are all less than 48, so we detect the
presence of a function (rather than a function
name
) by checking the
input string for ascii values less than 48. If this is the case, we make
the input string into an inline function before passing it to
feval
:
function funplot(f,lims)
% Simple function plotter.
% Test for characters whose presence would imply that f
% is a function (not a function name):
if any(f<48)
f = inline(f);
end
