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Procedural LECTURE Programming
The design focuses on steps that must be executed executed to achieve a desired state. One typically represents data as individual variables or fields of a structure and implement operations as functions that take the variables as arguments. Programs usually call a sequence of functions, each one of which is passed data, each and then returns modified data. Each function performs an operation or perhaps many operations on the data.
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Object-Oriented Programming Classes & Objects
E7, Fall 2008, M. Frenklach
Object-Oriented Design
Object-Oriented Design
A class describes a set of objects with common characteristics. Objects are specific instances of a class. The values contained in an objects properties are what make an object different from other objects of the same class class. The functions defined by the class (called methods) are what implement object th behaviors that are common to all objects of a class (you can add two doubles regardless of their values). 4
defines objects, that:
organize (systematize) data define methods (functions) link data and methods protect data hide implementation (complexity)
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properties
class: automobile automobile color design weight move stop accelerate
properties
object:
Honda Civic
>> x = 5 x= 5 >> class(x) class(x) ans = double >> methods(x) Methods for class double:
abs accumarray acos acosh all amd and any asin asin asinh atan atan2 atanh balance bitand bitcmp bitget bitor bitset bitshift bitshift bitxor bsxfun ceil chol cholinc cholupdate colon conj contourc conv2 cos cosh cosh ctranspose cumprod cumsum delete det diag diff display dmperm eig eps eps eq exist exp fft fftn fftw filter filt find finite fix floor full full ge gt hess hypot ifft ifftn ilu imag inv isfinite isinf isinf isnan issorted jit_breakpoint ldivide ldl le linsolve li log log2 logical lt ltitr ltitr lu luinc max mimofr min minus mldivide mod mpower mrdivide mtimes mtimes ne nnz nonzeros norm not nzmax or ordeig ordqz ordschur permute plus plus pow2 power prod qr qrupdate qz rcond rdivide real reallog realpow realpow realsqrt rem reshape round schur sign sin sinh sort sparse sparsfun sqrt sqrt sum superiorfloat svd tan tanh times transpose tril triu trmginput uminus uminus uplus xor
methods
red 4-door sedan sedan 1255 kg
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radar.m
%% create a conversion function: degrees -> radians deg2rad = @(degrees) degrees * pi / 180; %% set the initial geometry points = [1 -1 -1 1 [1 1 1 -1 -1]; %% set the rotation angle and convert it to radians angle = -1; phi = deg2rad(angle); %% execute rotation newPoints = rotate_array(phi,points); %% execute rotation w = 1; set(gcf,'KeyPressFcn','w = 0'); while w points = rotate_array(phi,points); rotate_array.m drawnow plot_points(points) function newPoints = rotate_array(phi,points) end % newPoints = rotation6(angle in radians,points) % rotation of coordinate axes rotationMatrix = [ cos(phi) -sin(phi) sin(phi) cos(phi) ]; cos(phi) ]; newPoints = rotationMatrix * points;
classdef Untitled %UNTITLED Summary of this class goes here % Detailed explanation goes here properties end methods end end
plot_points.m
function plot_points(points) % plot points given their coordinates plot points given their coordinates fill(points(1,:), points(2,:),'r') axis([-2 2 -2 2]) axis equal
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classdef radar % E7, Fall 2008, M. Frenklach properties Points = []; Color = ''; Direction = []; % +1 or -1 [] Phi = []; % in degrees Delay = []; end methods function obj = radar(p,c,d,angle,del) radar(p obj.Points = p; obj.Color = c; obj.Direction = d; obj.Phi = angle; obj.Delay = del; del; end 9 ...
%% set the initial geometry clear classes,clc points = [1 -1 -1 1 [1 1 1 -1 -1]; %% create a new radar object myRadar = radar(points,'r',1,10,0.5); >> properties(myRadar) Properties for class radar: Points Color Direction Phi Delay >> methods(myRadar) Methods for class radar: plot radar rotate rotate1
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% Positioning a radar %% set the initial geometry clear classes,clc classes points = [1 -1 -1 1 1 1 -1 -1]; %% create a new radar object myRadar = radar(points,'r',1,10,0.5); %% rotate myRadar.rotate
Protecting Data
classdef radar2 % E7, Fall 2008, M. Frenklach properties Color Direction Phi Delay end
= = = =
''; []; []; [];
% +1 or -1 % in degrees
properties (SetAccess = 'private') Points = []; []; end methods 12 function obj = radar2(p,c,d,angle,del)
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Setting Public Property
>> myRadar.Color ans = r >> myRadar.Color = 'b' myRadar = radar2 properties: Color: 'b' Direction: 1 Phi: 10 Delay: 0.5 Points: [2x4 double] list of methods
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Setting Private Property
>> myRadar.Points ans = 1 -1 -1 1 1 -1
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>> myRadar.Points = [-1 1 1 -1; 1 1 -1 -1] ??? Setting the 'Points' property of the th 'P th 'radar2' class is not allowed.
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function y = plus(obj1,obj2) for r = obj1.Reaction if ~isempty(r.with) && ... strcmpi(r.with.Formula,obj2.Formula) y = r.make; return end y = []; end end function display(b) name = [b.Formula ' ' b.Name]; if isempty(b.Image) disp(name) else figure('NumberTitle', 'off',... 'Resize','off',... 'MenuBar', 'none',... 'Color','white',... 'Name', name); imagesc(b.Image); set(gca,'Position',[0 0 1 1]); colormap(gray(2)); axis image off end end
Summary: What did we learned today?
CLASS: defines objects
Attributes and behavior
Method Overload
OBJECT
Properties internal variables Methods functions, method overload Events (we did not talked about it)
EXAMPLE: class radar
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