MATLAB SELECTION STATEMENTS (IF & SWITCH). KURSUS MATLAB ONLINE Skripsi, Tesis, DISERTASI 081219449060

MATLAB SELECTION STATEMENTS (IF & SWITCH)   >> aBin = '10011010', aDec=bin2dec(aBin) aBin = 10011010 aDec =    154 >> bBin ='11110001', bDec=bin2dec(bBin) bBin = 11110001 bDec =    241 >> andResult=bitand(aDec,bDec), andBin=dec2bin(andResult) andResult =    144 andBin = 10010000 >> orResult=bitor(aDec,bDec), orBin=dec2bin(orResult) orResult =    251 orBin = 11111011 >> shift2=bitshift(aDec,2), shiftBin=dec2bin(shift2) shift2 =    616 shiftBin = 1001101000 20.9       Review • Boolean expressions for selective application of formulae or execution of code • Relational operators in Matlab • Logical arrays • find() function • NaNs & empty arrays • base conversion 21           MATLAB SELECTION STATEMENTS (IF & SWITCH) • Selection between alternate paths in code execution is a vital component of modern programming languages: - allows the conditional execution of code • Most non-trivial programs (e.g., 50-lines+) in most programming languages are guaranteed to have one or more IF-statements.

- Matlab is one of these exceptions due to boolean operations on arrays.

• Matlab provides two versions of the selection statement: - IF/IF-ELSE/IF-ELSEIF -              SWITCH-CASE • Today’s lecture covers: -              reasons for the widespread usage of Selection statements -              syntax of Selection statements in Matlab.

References:        For Engineers (Ch. 1, 7)                                                             Mastering (Ch. 13)                                                             Student (Ch.. 11) 21.1       Motivation • Branching (selection between alternates) is a vital tool in solving most problems by computer: -              sequential execution implies that the same code is executed every time regardless of inputs or other conditions -              selection allows the execution of the appropriate code for the current situation (set of values) • Examples include: -              menu choices if choice is “New” then                create a new document else if choice is “Save” then                save the current document : else if choice is “Quit” then                finish program -              error catching if can’t open file then                print error message and quit.

Kami ada di Jakarta Selatan. KAMI MEMBERIKAN KURSUS MATLAB ONLINE - HUBUNGI MASTER ENGINEERING EXPERT (MEE) 081219449060.  Kami membuka kursus Matlab untuk pemula dan mahasiswa atau insinyur yang ingin memperdalam Matlab dan menerapkan dalam bidang teknikal, engineering, rekayasa, dsb. Format bimbingannya tugas-tugas yang bisa membantu Skripsi, Tesis, DISERTASI Bimbingan dilakukan secara online bisa lewat WA atau email Dijamin Bisa, atau bisa mengulang kembali. Kami juga dapat membantumembuatkan aplikasi atau program matlab/lainnya. Anda akan dilatih oleh Tim Profesional - HUBUNGI MASTER ENGINEERING EXPERT (MEE) 081219449060.   Email: kursusmatlab@gmail.com

-              special-case handling & variable outputs if cost<1.0   fprintf(‘Price less than one dollar’); else   fprintf(‘Price less than %d dollars’,…         ceil(cost)); end; 21.2       Simple IF • Simplest form of IF statement: - conditional execution of a single set of statements • Schematic form:                statement_before;                if test                                statement(s)_1;                end;                statement_after; • test is a boolean expression (evaluates to true or false) - c.f. previous lecture on relational operators 21.3       Examples – Simple IF price = input(‘Please enter a price for the item ‘); if price<0   disp(‘A negative price input. Resetting to positive’);   price = -price; end; fileName = input(‘What is the name of the file containing the data ‘,’s’); descriptor = fopen(fileName,’r’); if descriptor==-1   error(‘Unable to open file for reading. Quitting’); end; if count~=0   average = total/count; end; 21.4       IF-ELSE • Often desirable to make a choice between two alternates: - do one or the other but not both • Schematic:                statement_before;    if test      statement(s)_1;    else      statement(s)_2;    end; • Note layout convention & indentation 21.5       Example – IF-ELSE val = input(‘Please input a value ‘); if val<0   result = -val; else   result = val; end; printf(‘The absolute value of %d is %d\n’,...

val,result); digit = input(‘Please enter a single digit ‘); if digit<10 & digit>=0   fprintf(‘%d^%d is %d\n’,digit,digit,digit^digit); else   fprintf(‘Sorry, that was not a single positive digit’); end; if teamAScore>teamBscore   disp(‘Team A was the winner’); else   disp(‘Team A did not win’); end; fileName = input(‘What is the name of the file containing the data ‘,’s’); descriptor = fopen(fileName,’r’); if descriptor==-1   error(‘Unable to open file for reading. Quitting’); else   values = fscanf(descriptor,’%f’); end; 21.6       IF-ELSEIF-… • Often (and more generally) it is desirable to select one option (code segment to execute) from multiple possibilities • Schematic                statement_before;                if test1                  statement(s)_1;                elseif test2                  statement(s)_2;                elseif…                  :                elseif testn                  statement(s)_n;                else                  statement(s)_n+1;                end;                statement_after; • Performs each of the checks in turn: -              as soon as first evaluates to true performs corresponding statements & finishes -              if no test evaluates to true then performs statements under else (which must be final) IF-ELSEIF… (Cont) 21.7       Example – IF-ELSEIF… %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % finalMark.m %  Calculate a student's final mark in Computer %  Tools based on a final lab and exam mark, %  plus whether they completed all competency %  exercises.

%  An illustration of the IF-ELSEIF construct.

Kami ada di Jakarta Selatan. KAMI MEMBERIKAN KURSUS MATLAB ONLINE - HUBUNGI MASTER ENGINEERING EXPERT (MEE) 081219449060.  Kami membuka kursus Matlab untuk pemula dan mahasiswa atau insinyur yang ingin memperdalam Matlab dan menerapkan dalam bidang teknikal, engineering, rekayasa, dsb. Format bimbingannya tugas-tugas yang bisa membantu Skripsi, Tesis, DISERTASI Bimbingan dilakukan secara online bisa lewat WA atau email Dijamin Bisa, atau bisa mengulang kembali. Kami juga dapat membantumembuatkan aplikasi atau program matlab/lainnya. Anda akan dilatih oleh Tim Profesional - HUBUNGI MASTER ENGINEERING EXPERT (MEE) 081219449060.   Email: kursusmatlab@gmail.com % Author: Spike % Date:   11/3/1999 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% lab = input('Please enter the lab mark as a percent [1-100] '); exam = input('Please enter the exam mark as a percent [1-100] '); competent = input('Did the student complete all competency exercises [y/n]? ','s'); initialTotal = (lab+exam)/2; if initialTotal>39 & ~ strncmp(competent,'yes',1)   finalTotal = 39; elseif initialTotal>39 & lab<40   finalTotal = 39; elseif initialTotal>39 & exam<40   finalTotal = 39; else   finalTotal = initialTotal; end; fprintf('The final mark for the subject is %5.1f%%\n',finalTotal); if finalTotal~=initialTotal   fprintf('\t Reset from %5.1f%% due to failure of a component\n',initialTotal); end; 21.8       Truth Tables & Compound IFs • IFs may be nested (placed one inside the other).

- also called compound • Often hard to follow logic of the code -              indentation helps readability -              truth tables help • For example: if test1   statements_1;   if test2 & test3     statements_2;   else     statements_3;   end; elseif test4   statements_4 else   statements_5; end; T1           T2           T3           T4           S1           S2           S3           S4           S5 T             F             F             *             Y                            Y                            T             F             T             *             Y                            Y                            T             T             F             *             Y                            Y                            T             T             T             *             Y             Y                                           F             *             *             F                                                                         Y F             *             *             T                                                          Y             Compound IFs (Cont) %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % finalMark2.m %  Calculate a student's final mark in Computer %  Tools based on a final lab and exam mark, %  plus whether they completed all competency %  exercises.

%  A variant on the finalMark script which shows %  an alternate approach to the IF-ELSEIF %  construct as nested (compound) IFs.