<p>% Agenda -Structure Arrays -Recursion 2D-Plotting</p><p>%%% We want to make this Structure %%%%%%%%%%%%% ans = </p><p>1x46 struct array with fields: TW LW Title Studio Weekend_gross Weekend_change Theater_count Theater_change Average Gross Budget Week %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% function mv = make_movies clc fh = fopen('movies.txt','r'); line = fgetl(fh); mv = []; while ischar(line) line = fgetl(fh); if ischar(line) mv = [mv make_movie(line)]; end end end</p><p>%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% function mv = make_movie(line) % Header Record % TW|LW|Title|Studio|Weekend|Gross|%Change| ... % Theater|Count|Change|Average|Total Gross|Budget|Week| % Typical Data % 1|2|Identity Thief|Uni.|$14,064,000|-40.6%|3,222|+57|$4,365|$93,667,000| $35|3 % Both tab delimited [token line] = strtok(line, char(9)); mv.TW = getNum(token); [token line] = strtok(line, char(9)); mv.LW = getNum(token); [token line] = strtok(line, char(9)); mv.Title = token; [token line] = strtok(line, char(9)); mv.Studio = token; [token line] = strtok(line, char(9)); mv.Weekend_gross = getNum(token); [token line] = strtok(line, char(9)); mv.Weekend_change = getNum(token); [token line] = strtok(line, char(9)); mv.Theater_count = getNum(token); [token line] = strtok(line, char(9)); mv.Theater_change = getNum(token); [token line] = strtok(line, char(9)); mv.Average = getNum(token); [token line] = strtok(line, char(9)); mv.Gross = getNum(token); [token line] = strtok(line, char(9)); mv.Budget = getNum(token); [token line] = strtok(line, char(9)); mv.Week = getNum(token); end</p><p>%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% function res = getNum( str ) str = str(str ~= ' ' & str ~= '$' & str ~= ',' & str ~= '%' & str ~= '+'); if length(str) == 1 && (str(1) == '-' || str(1) == 'N') res = NaN; else res = str2double(str); end end</p><p>%%%%%%%%%%%%%%% Movie Questions %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% clear clc mv = make_movies % total gross take this weekend gross = [mv.Weekend_gross]; gross = gross(~isnan(gross)); %skips the NANs sumMills = sum(gross) ./ 1000000; fprintf('total take was $%5.3f million\n\n\n', sumMills) % rank movies by Average field (gross per theater) avgs = [mv.Average]; avgs = avgs(~isnan(avgs)); %skips the NANs [~, order] = sort(-avgs); fprintf('ord\ttheaters\tname\n') for ndx = 1:8 mvndx = order(ndx); it = mv(mvndx); fprintf('%d\t\t%d\t%s \n', ndx, ... it.Theater_count, it.Title) end</p><p>****** Example: Structures from Spreadsheet ********* function im_really_a_script str = get_grades('gradeSheet.xls', 2, 'L'-'A', 2); % display the structures for st = str st end end function stra = get_grades(name, hdrrow, cols, left) % field names are on row 'hdrrow' of the text file: % there are 'cols' fields to process % there are 'left' tezxt columns to the left of the nums array</p><p> clc</p><p>% initialize the structure array to empty [nums txt ~] = xlsread(name); [nrows ~] = size(nums); for student = 1:nrows str = struct(); for col = 1:cols % extract the field name from the header row name = txt{hdrrow, col}; % determine if this field contains a vector [numeric, field, ndx] = has_num(name); % for each student</p><p>% find the row in the txt array row = hdrrow + student; % get a numeric value from the nums array if numeric value = nums(student, col - left); % get a text value from the txt array else value = txt{row, col}; % if the string is empty, it's really a non-indexed number if length(value) == 0 % so get its value from the nums array value = nums(row - hdrrow, col - left); end end % insert the value in the right place in the structure: % % if the field exists and is numeric, put the value % in the correct index position in the field if isfield(str, field) % fetch the previous field contents now = str.(field); % add the new value now(ndx) = value; % put it back in the field str.(field) = now; % otherwise, just put the value whatever it is in the field else str.(field) = value; end end stra(student) = str; end end</p><p>******* find a number ************ function [res, field, ndx] = has_num(name) res = false; field = name; ndx = 1; n = find(name >= '0' & name <= '9'); res = length(n) > 0; if res num = name(n); ndx = str2double(num); field = name(1:n(1)-1); end end</p><p>Recursion</p><p>Recursion is a big deal</p><p>Tell Us a Story</p><p>General Says, It was a dark rainy night and the men were gathered in the mess hall after Battle, General Says, Young Colonel tell us a story</p><p>Factorials Fibonacci Palindrome But how does it work (Use of a Stack) Cafeteria Golden Corral</p><p>What does Recursion Require? 1. Termination Condition 2. Call the Clone (same function) 3. Move towards Termination Condition</p><p>****** Function fact ******* function res = fact(N) if N < 0 || mod(N,1) > 0 error('no, not a good number...') % called a wrapper else res = rfact(N); end end</p><p>**** Real Function ***** function res = rfact(N) % 1. have a terminating condition if N == 0 res = 1; else % 2. call a clone of the original function % vvvvv res = N * rfact(N-1); % ^^^ % 3. parameter(s) of that call must move towards % the terminating condition end end ***** Darn those Rabbits ******* Text Chapter 9 ***** ****** Fibonacci Series ****** function res = fib(N) % Recursion of the Nth Fibonacci if N == 1 || N == 2 res = 1; else res = fib(N-1) + fib(N-2); end end</p><p>****** Is a Palindrome ******* zerorez never odd or even function YesNo = isPal(str) % recursive palindrome detector if length(str) < 2 YesNo = true; elseif str(1) ~= str(end) YesNo = false; else YesNo = isPal(str(2:end-1)); end end</p><p>2D-Plotting ______Basic Plotting______</p><p>----2-D Plots ----- together x = linspace(-1.5, 1.5, 30); y1 = x; y2 = x.^2; y3 = x.^3; y4 = x.^4; plot(x,y1,x,y2,x,y3,x,y4)</p><p>----2-D Plots ----- separate clf x = -2*pi:.05:2*pi; subplot(2,3,1) plot(x,sin(x)'); title('1 - sin(x)') subplot(2,3,2) plot(x,cos(x)) title('2-cos(x)'); subplot(2,3,3) plot(x, tan(x)); title('3-tan(x)'); subplot(2,3,4) plot(x,x.^2) title('4-x^2')</p><p>----- 2D Plots – </p><p>______example curves ______clear clc close all th = linspace(0, 6*pi, 210); p1 = sin(th); plot(th, p1) hold on plot(th, cos(th), 'r--') t1 = tan(th) %t1(abs(t1) > 2) = NaN; plot(th, t1, 'g.') axis([0 20 -2 2]) legend({'sin(th)','cos(th)', 'tan(th)^2'})</p><p>______3-D Plots ______clear clc close all</p><p>% plot a function x = linspace(-4*pi, 4*pi, 200); y = sin(x); z = x .^ 2; plot3(x, y, z) hold on plot3(x, y, z, 'ro') grid on xlabel('x') ylabel('sin x') zlabel('x^2') % parametric plot (two dependent variables) figure th = linspace(0, 2*pi); plot(cos(th), sin(th)) axis equal</p><p>______MyTree with Wrapper ______function myTree hold on treeR(0,0,10,0) end function treeR(x, y, ln, th) x1 = x + ln .* sin(th); y1 = y + ln .* cos(th); if ln < 0.15 plot([x x1], [y y1], 'g') else plot([x x1], [y y1], 'k') rn = rand(1,3) - 0.5; newL = ln * 0.7; %try 0.6 treeR(x1, y1, newL, th+rn(1)) treeR(x1, y1, newL, th+rn(2)) %treeR(x1, y1, newL, th+rn(3))</p><p> end end</p>