User Defined Functions7

8/18/2019 User Defined Functions7

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User-Defined Functions

charturong.ee.engr.tu.ac.th/CN208

! !" #

# $ # % &' ( )'! ' . !


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Introduction

'%! * )$ top-down design )'!$ + , +- , $. $ + !-!/01 2 - ! - 3, 3 & 13%! )$ $ + !-!/ -% & - % 2 ()$

!-!/ - % & 4 2 , $ + , +-% 2 % , )$ top-down design % & )$

MATLAB , 5 *3%! % ) # 3%! 2(function) 3 )'! 3%! 1 2 2#( 1 2 $ + !-! & 5 *3%!# 6 ( 2 -% & 4 2 $ + , +-% 2 '

M-files % 2 '71 3%! & ' - , - 2 -$.script files( (# 2MATLAB $ ! , , 1 2 )$ )


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1. # ' -! -31 & )$ 4 2 (independent testingof sub-tasks)2. # 6 (, '% ! &(reusable code)3. $ 3 5' ' ''%(isolation fro unintended side effects)


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3%! MATLAB 2 3%! $.M-file 8 % 2( )'!%*$ ' - $ % &

function !outarg1" outarg2" #$ % fna e(inarg1" inarg2" #)

& '1 co ent line& t er co ent lines

(*+ecutable code)

#

(end)


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(# 2function , #' ' 2 3 2 , ' (# 2function - 4 2 3 2 3 * % 2, (input) 5 "

3 2(output)

)'! % 2input argu ent list (inarg1" inarg2"

#) $ 9, 4 2 ! .( ) (parent eses) 4 2 32 output argu ent list (outarg1" outarg2" #) $9, 4 2 ! .#% 2 % 2! ! $ (brackets) ' 0! 43

4 2 ! - 6 % output - output '%! -( $. , 4 2 ! . #% 2 % 2!

- 2 6*0 $.. file )'!, 4 2 3 $. 4 2'%! 4 2 2 246 & 4 2 2-M, fun

2 & 6*0 )'!, 4 2 M, fun.


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, input argu ent list 4 2 ( 3 $ % 2 , ,2 & 4 2 3 $ & $. $ 2 4du ,

argu ent 01 2 ,#( - 3* % 2 % 2 26* %! , 4 2 3 $ -% & 6*(' & % 2 MATLAB$ 5 2 & # .# &

, output argu ent list 4 2 ( 3 $ % 2 2 &

,5 " % 2 2 & ( $ 5 01 2 % ( ! input argu ent list, (# 2end 4 2 -$.'# & #'3 2% 2,

& - MATLAB ./ $. $ 01 2 3%! (# 2end 4 22 & 3%! 4 -3%! . ' 3%! (# 2end 4 22 '! 3%! co ent 4 2 -#( 2


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3%! co ent ' , 2 4% 2 %! -'1co ent line & , 4 2 % 2 4'$ # 3 2 &01 2co ent ' % 8 % 2 6* #' 5

4 2 , (# 2lookfor , - (# 2, MATLAB #-co ent ' % 2 4 % 2 '1 co ent line

261 ' - ' 4(# 2% 2( ' 3MATLAB 6*#' )'!, (# 2elp


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1function distance % dist2 (+1" ,1" +2" ,2)& dist2 calculates t e distance between two points& 0unction dist2 calculates t e distance between& two points (+1" ,1) and (+2" ,2) in a artesian

& coordinate s,ste

& alculate distancedistance % s rt((+2-+1). 2 4 (,2-,1). 2)5

end & function distance


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6 4 2 3%! 2dist2 # . , 0 :'' # )'!,

4 2 dist2.6 - (# 23 MATLAB (co and window) # 6 , (# 2lookfor 4elp 4 2 ( ( % 2! 2dist2 01 2MATLAB #' 5 " (# 2% 2%4 2 dist2 ' % &77 lookfor dist2

dist2 calculates t e distance between two points89:T2:T; 8istance con


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dist2

# 6 %! , 2dist2 '# "% 41. , -co and window )'! - ! -'

(/" 1) ' (2" >) . ( ' ' % &77 out % dist2 (/" 1" 2" >)out % 3.?/@?

01 2 .' -5 " 3 2dist2 -( $. , 4 2$ -distance - $. 4 2 $ ,'/ . '

2. 3%! %! , ,script file 4 %! , 2MATLAB 2$


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script file& :cript file test dist2.&& urpose T is progra tests function dist2

& Cet input datadisp( D alculate t e distance between two points D )5a+ % input(D*nter +


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01 25 "3 run 3 script file 3 % 2 4 2 test dist2 %' % &77 test dist2

alculate t e distance between two points*nter +


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23%! 2 4 2 $ & '3 3 ( .

% 2 ( ', ( ', 2%*$ %! , 4fac %find factor(nu ) )'! % 2 nu $. 3 ( . fac $. % 2 % $ 3 3nu $.

#


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function fac % find factor(nu )

& find factor finds all of t e factors of a positi


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!"#!$

)$ MATLAB , % 2 %! - pass-b,-


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! !- 5-- $ pass-b,-.2f &>.2fFnD" a" b)5a % b(1) 4 2Ha5

b % a .H b5out % a 4 b(1)5fprintf( D9n function sa ple a % &>.2f" b % &>.2f &>.2fFnD" a" b)5

# 6 ' 5-- $ )'! 3%! script file 4 2test sa ple. ' % &a % 25 b % !? >$5

fprintf( DBefore function sa ple a % &>.2f" b % &>.2f &>.2fFn D" a" b)5out % sa ple(a" b)5fprintf( DAfter function sa ple a % &>.2f" b % &>.2f &>.2fFn D" a" b)5fprintf( DAfter function sa ple out % &>.2fFn D" out)5


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5 " % 2 ' $ 5 )$test sa ple , - (# 24

77 test%sa&pleBefore function sa ple a % 2.//" b % ?.// >.//

9n function sa ple a % 2.//" b % ?.// >.//9n function sa ple a % 1/.//" b % ?/.// >/.//After function sa ple a % 2.//" b % ?.// >.//After function sa ple out % /.//

01 2 . ' - - 3 $a b 6* $ % 2! !, 2sa ple - $ % 2! $ % & - % 5 - $ ;


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'sorting(

%! 3(sorting) 4 ( 3 & ', < 3* '(' $! 4 ! $ 01 2 %! 3 % & %$ )! !-71 %! 3 !- *$. $ ( 1 (,$ + % &'*$. 4 2 % 2- !

%! !1/ 3 -1 @ I$ ! $ $.!-1 3 @ I 1/$ % &(' !- J3 & %! 3 % 2 ! 4 3 % 2 %- ! % 2#'

3 &@ - 01 2 24 3-1 & 13 % 2 ! % 2#' - $, 3 % 2 4!1/ 3 @ I$ 01 2 4

3 ( !- % & -$ 4 2 ! 23 & '6*%!%! 3 % & %! -selection sort


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)election )ort%! 3 % 2 %! -:election :ort 4 %3 2

-! % 2#' 01 2 %! ! $ (' !- % 2 ' - ,4 &1. 3 % 2 % -! % 2#', (- 3 &

$. #'3 6 )'!# $ % 2! 3 & 3 36 -6 - 3 6 % -!#' !- * -(

2. 3 & -% 2 2 $. $ 4 2 3 % 2%- !% 2#' - $ ( # $ % 2! 3 & 3 % 2# 36 -6 - % 2# 3 6 % -! % 2#' $. % 2# !- *

- (3. ( % & $ 4 2 !/ 24 - 2 #' ! ( # $ % 2! 3# #' !, $.

%! 3


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1/ 3 -1 @ I

-1 3 1/ @ I

#

- #

-1 3 1/ @ I

#-1 3 @ 1/ I

-1 3 @ I 1/

#


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selection%sort'arr(

# 6 3%! pseudocode #( selection sort '' -$ % &

for (eac inde+ position ii in t e arr)find kk (t e inde+ t e s allest


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function out % selection sort(arr)& selection sort sorts data in ascending order

n


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function ind % find s allest nu ber(arr" ii)& find s allest nu ber finds t e inde+ of t e s allest nu ber in arr between ii

& and t e end of t e arr

n


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$u**le )ort

%! 3 bubble sort 2 %! )'! $ %! %!32 , < 3 * # $ % 2! ( - 32 % &,!- * , ( - % 26* & ( $ %! %! 3 % 22

% 23 , < 3 * - $ ( #$ % 2! ( -6( $. ( % & -$ 4 2 !/ 6 & 2$ %! %! 32 , < 3*, - % & -$ 4 2 !/- & -% # $ % 2! '31 & 1$. !

3 bubble sort


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!- %! 3 bubble sort 3 !1/ 3 -1 @ I$ ( '' % &%! % 21

!1/ 3 -1 @ I$ !3 1/ -1 @ I$ ' '2 3!3 1/ -1 @ I$ !3 -1 1/ @ I$ ' ' 2 3 -$!3 -1 1/ @ I$ !3 -1 @ 1/ I$

!3 -1 @ 1/ I $ !3 -1 @ I 1/ $%! % 2 1 % # $ % 2! ( -> &%! % 22

!3 -1 @ I 1/$ !-1 3 @ I 1/$

!-1 3 @ I 1/$ !-1 3 @ I 1/$!-1 3 @ I 1/$ !-1 3 @ I 1/$!-1 3 @ I 1/ $ !-1 3 @ I 1/ $

%! % 2 2 % # $ % 2! ( -1 &


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%! % 23!-1 3 @ I 1/$ !-1 3 @ I 1/$!-1 3 @ I 1/$ !-1 3 @ I 1/$!-1 3 @ I 1/$ !-1 3 @ I 1/$

!-1 3 @ I 1/ $ !-1 3 @ I 1/ $ %! % 2 3 % # $ % 2! ( -0 & ; &%! bubble sort


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*u**le%sort'arr(

# 6 3%! pseudocode #( selection sort '' - $ % &w ile swap occurs

& co pare two ad acent nu bers and swap t eir positions if necessar,for ii % 1 (n


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function out % bubble sort(arr)& bubble sort sorts data in ascending order

swap % 15n


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+ptional !rgu&ents

2MATLAB % , $ % 4 -% . ' (optional input and output argu ents) ! !- - , 2 plot01 2 %$ & -2 $ 61 - $. 01 2MATLAB * ' !- - 2-% & %$ 4 % 2

MATLAB % 2 8#( - ( $ , 2 #' (4 ' - $ % &

6 nargin N , -( 3 $ , 26 nargout N , -( 3 $, 26 nargc k N #' 3 -% 5 ' ')'!) 6 % 26*

%! %( $ 4 4! $6 error N #' 3 - %3 5 ' '(error essage) ! %26 warning N #' ( 4 - , 2( - $6 inputna e -- , 4 2 3 $ ( -% 26*


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1. 2nargin nargout 6* %! , !, 3%!2 01 2, -( $ % 2 26* %! ,

2. 2nargc k # 3 % 2 #' 3 5' '6 2%($ 4 ! $ % *$ , 4essage % nargc k( in args" a+ args" nu args)5

)'! % 2 in args $. ( ! % 2#'3 $ % 2 $. $ ' a+ args$. ( % 2#'3 $ % 2 $. $ ' nu args $. (

$ % 2 % 26* %! , 6 ( $ -!- * !, ( % 2( ' 3 5' ' 6*#' ) , $ essage3. 2error , #' 3 -%3 5' ' ! %!

2 & )'! % %! , 4error(O sgP) )'! % 2 sg 43 2( ', #' 3 5 ' ''31 &


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>. 2warning , #' ( 401 2 4 2 2 ' % 2$ + '31 & -$ -!, 2( -$ )'! % ,4warning(O sgP) )'! % 2 sg $. 3 % 2 #' ( 4@. 2inputna e , #' 4 2 3 $ % 2 26* %!

, %*$ ,4na e % inputna e(argno)5 )'! % 2argno $.( -3 $ -

function ,fun(+" ," Q)na e % inputna e(2)5disp(! DT e second argu ent is na ed D na e$)5

4 2 2% &6* %! , , - (# 2 5 "477 dog % 15 cat % 2577 ,fun(dog" cat)T e second argu ent is na ed cat


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optional argu&entsfunction ! ag" angle$ % polar


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& eck for (/"/) input argu ents" and print out a warning essageif + %% / R , %% /

sg2 % DBot + and , are Qero angle is eaningless.D5warning( sg2)5

end

& Sow calculate t e agnitude.

ag % s rt(+. 2 4 ,. 2)5

& 9f t e second output is present" calculate angle in degrees.if nargout %% 2

angle % atan2(," +) H 1I/Gpi5end

end & function polar


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polar%,alue

%! , 2 polar


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2. '# ,(# 2warning 4 2 + % / , % /77 ! ag angle$ % polar


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3. '# , 2 polar


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>. '# , 2 polar

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User Defined Functions7

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