MATLAB: Set(handle.blabla, ‘String’, num2str(x)) is never appeared. What should I do

MATLABmatlab gui

I'm building a Class A Amplifier GUI to define the required value of resistors and the output voltage. I'm using Matlab GUI, R2012b. The formulas and other syntax I used were okay, there's no error message. But the resistor value is never appeared. How can I make it appears? Thx
Here is the code I use for the GUI.
function hitung_Callback(hObject, eventdata, handles, varargin)
% hObject    handle to hitung (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
kelasA=guidata(hObject);
O = get(kelasA.Ic,'string');
vin = get(kelasA.teg_input,'string');
Vcc = get(kelasA.Vcc,'string');
N = get(kelasA.hfe,'string');
O = str2num('O');
N = str2num('N');
Vcc = str2num('Vcc');
Vin = str2num('Vin'); 
A = times(0.5,O);
B = times(0.1,Vcc);
C = B+0.7;
D = C./O;
E = times(4,D);
P = O./N;
G = times(10,P);
G = str2num('G');
C = str2num('C');
H = Vcc/G;
I = C/G;
I = str2num('I');
J = H-I;
J = str2num('J');
K = 0.025./O;
K = str2num('K');
D = str2num('D');
E = str2num('E');
L = (I*(N*(K+D)))/(I+(N*(K+D)));
L = str2num('L');
M = times(Vin,(E/L));
M = str2num('M');
set(kelasA.r2, 'String', num2str(D));
set(kelasA.r3, 'String', num2str(I));
set(kelasA.r4, 'String', num2str(J));
set(kelasA.vout, 'String', num2str(M));
set(kelasA.r1, 'String', num2str(E));
%

Best Answer

We as onlookers who do not have your full code, do not know that the items being set are on-screen and not covered up by anything else.
But probably more important to you: try this:
Vcc = '456';
disp('Interpreting Vcc')
str2num('Vcc')
J = 12345;
disp('Interpreting J')
str2num('J')
disp('trying Vcc again')
str2num(Vcc)
Related Question