Creating an array of objects in a class

I have two .m files for class tree and class leaf:

classdef Tree
    properties
        leaves = [];
        for i = 1:100
            leaves = [leaves Leaf]
        end
    end
    %
    methods (Static = true)
        function show
            for i = 1:100
                leaves(i).show
            end
        end
    end
end

and

classdef Leaf
    properties
        pos = [rand*200 rand*200]
    end
    methods (Static = true)
        function show
            disp('this is a leaf')
        end
    end
end

I'd like to be able create a Tree object with an array of Leaf objects. How may I do this? I'd also like to make the "show" function work.

Thanks!

Answer 1

[Robert U]

Hi Jeffrey,

here my solution for your tree with leafs:

Tree.m:

 classdef Tree

    properties
        leaves = [];
    end

    methods
        function obj = Tree(nLeaves)
            obj = obj.CreateLeaves(nLeaves);
        end

        function obj = CreateLeaves(obj,N)
            for ik = 1:N
                if ~isempty(obj.leaves)
                    obj.leaves(end+1) = Leaf();
                else
                    obj.leaves = Leaf();
                end
            end
        end

        function showTree(obj)
            if ~isempty(obj.leaves)
                fprintf('The tree has %d leaves.\n\n',length(obj.leaves));
                for ik = 1:length(obj.leaves)
                    fprintf('Leaf %d:\n',ik);
                    obj.leaves(ik).show;
                end
            else
                fprintf('The tree has no leaves.\n');
            end
        end
    end
 end

Leaf.m:

 classdef Leaf

    properties
        pos = [];
    end

    methods
        function obj = Leaf(~)
            obj = obj.RandomPos;
        end

        function show(obj)
            fprintf('This is a single leaf at (%.2f, %.2f).\n\n',obj.pos(1),obj.pos(2))
        end
    end

    methods (Access = private)
        function obj = RandomPos(obj)
            currSetting = rng;
            rng('shuffle');
            obj.pos = [rand*200 rand*200]; 
            rng(currSetting);
        end

    end
 end

Create a tree with 5 leaves:

 myTree = Tree(5)

Show full tree:

 myTree.showTree

Show a single leaf:

 myTree.leaves(4).show

[Robert U]

It is not a "safe" solution. Unsupported inputs are not detected (e.g. Nleaves = 0).