How do I change the line color and line width of a graph plotted through a GUI?

So I'm trying to change the line color and line width of a graph plotted in through a GUI I made in matlab, but I'm not sure how to do it.. the code I have for plotting the graph so far is as follows:

    % --- Executes on button press in pushbutton_solve.
function pushbutton_solve_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton_solve (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
a = str2num(get(handles.value_a,'string'));
b = str2num(get(handles.value_b,'string'));
c = str2num(get(handles.value_c,'string'));
x = str2num(get(handles.x_min,'string')):str2num(get(handles.x_increment,'string')):str2num(get(handles.x_max,'string'));
y = a*x.^2 + b*x + c;
axes(handles.axes1);
plot(x,y)
xlabel = ('x-value');
ylabel = ('y-value');
guidata(hOject,handles)

end

[Adam]

As an aside to the question, you should use the

plot( handles.axes1, x, y,... )

syntax, with the additions pointed out by KSSV in his answer rather than

axes(handles.axes1);
plot(x,y)

Your version works, but it is much better practice to get used to telling the plot function explicitly which axes to plot on rather than relying on having brought the right axes into focus beforehand.

Answer 1

[KSSV]

Read about plot

x = rand(10,1) ;
y = rand(10,1) ;
cs = 'r' ;
n = 2 ;
plot(x,y,'color',cs,'linewidth',n) ;