adding elements into a vector using MATLAB GUI

I am new to matlab and I'm trying to make a progrem which gets parameters from the user(using gui)for x value and y value,puts them into 2 different vectors and when the user is done it uses plot to make a graph out of the two vectors.

here is what I tries to do:

function pushbutton1_Callback(hObject, eventdata, handles)
x=[];
y=[];
a=str2double(get(handles.edit1,'string'));
b=str2double(get(handles.edit2,'string'));
handles.x=[x a];
handles.y=[y b];
guidata(hObject, handles);

function Doit_Callback(hObject, eventdata, handles)
axes(handles.axes1)
handles.x;
handles.y;
handles.m=handles.x;
handles.n=handles.y;
plot(handles.m,handles.n);
guidata(hObject, handles); 

function Doit_Callback(hObject, eventdata, handles)
axes(handles.axes1)
handles.x;
handles.y;
handles.m=handles.x;
handles.n=handles.y;
plot(handles.m,handles.n);
guidata(hObject, handles);

but the plot function won't work.I'm tring to get a and b from the edit text in the gui and put them into vector x and vector y,and when I'm done adding all the element I want I'm trying to use the full vectors in the Doit function. any help would be appreciated

[Walter Roberson]

Are a and b intended to be vectors? Because str2double() only works for strings representing scalars. If this is the problem then str2num() works on strings representing scalars -- but is more fragile and less secure, since it is happy to accept input such as

delete('*.*')

and act on it...

[elizabeth march]

No,a and b intended to sort the variables I get from the edit text boxes in the gui,and I want to insert a into x and b into y. x and y intended to be the vectors

Answer 1

[Walter Roberson]

You have

x=[];
y=[];

so you set x and y to empty arrays

a=str2double(get(handles.edit1,'string'));
b=str2double(get(handles.edit2,'string'));

so you get scalar a and b values from what the user entered

handles.x=[x a];
handles.y=[y b];

x and y are both empty because you set them that way, so this is equivalent to

handles.x = a;
handles.y = b;

which sets scalars. But it sounds like later you expect handles.x and handles.y to be a record of everything the user ever entered.

I suspect you want

if ~isfield(handles, 'x')
  handles.x = [];
  handles.y = [];
end

 a = str2double(get(handles.edit1,'string'));
 b = str2double(get(handles.edit2,'string'));
 handles.x(end+1) = a;
 handles.y(end+1) = b;

 guidata(hObject, handles);

Note: in your callbacks, the lines

handles.x;
handles.y;

are not doing anything useful and can be removed.

[elizabeth march]

Thank you!