MatLab Programming

Functions

Single Output function

   function out =fnName(param1, param2...)
    ...body
    end  
    

Multi Output function

   function [out1, out2, ..] =fnName(param1, param 2...)
     ...body  
    end   

eg:

  function y = squareThisNumber(x)
  y= x^2
  
  // Multiple Output
  function [y1,y2] = squareAndCubeThisNumber(x)
  y1= x^2
  y2= x^3

Anonymous function

• Returns only single output

• Can be pass as input to other function

• f is called Function Handle

  f = @(params..) expression

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Classes

A MATLAB class lives in its own file, named after the class, starting with classdef.

% File: Point.m
classdef Point
    properties
        x
        y
    end

    methods
        % Constructor — same name as the class
        function obj = Point(x, y)
            obj.x = x;
            obj.y = y;
        end

        function d = distanceFromOrigin(obj)
            d = sqrt(obj.x^2 + obj.y^2);
        end
    end
end

Usage:

p = Point(3, 4);
p.distanceFromOrigin()   % 5

Properties

Hold the state/data of an object — equivalent to fields/attributes in other OOP languages.

properties
    x
    y = 0          % default value
end

properties (Access = private)
    secret          % only accessible inside the class
end

Methods

Functions that operate on an object's properties. The first argument is conventionally obj.

methods
    function obj = setX(obj, newX)
        obj.x = newX;     % MATLAB objects are value types — must return obj
    end
end

Constructor

A method with the same name as the class, called automatically when you create an instance (Point(3,4)). If omitted, MATLAB provides a default constructor that takes no arguments.

Inheritance

A subclass extends a base class using < BaseClassName, reusing its properties/methods and overriding what it needs to.

classdef Point3D < Point
    properties
        z
    end

    methods
        function obj = Point3D(x, y, z)
            obj = obj@Point(x, y);   % call superclass constructor
            obj.z = z;
        end

        function d = distanceFromOrigin(obj)
            d = sqrt(obj.x^2 + obj.y^2 + obj.z^2);   % overrides Point's method
        end
    end
end

Encapsulation

Restrict direct access to internal state using Access attributes on properties/methods, exposing only what callers need.

properties (Access = private)
    balance = 0
end

methods
    function obj = deposit(obj, amount)
        obj.balance = obj.balance + amount;
    end

    function b = getBalance(obj)
        b = obj.balance;   % controlled read access, no direct external writes
    end
end