how do you put condition in GUI?

% I would like to put a condition that t3 is greater than t4,t2, and t1,t2 is less than t4 and t2>t1

% --- Executes on button press in Calculate.

function Calculate_Callback(hObject, eventdata, handles)

% hObject handle to Calculate (see GCBO)

% eventdata reserved - to be defined in a future version of MATLAB

% handles structure with handles and user data (see GUIDATA)

% Hint: get(hObject,'Value') returns toggle state of Calculate

t1=str2double(get(handles.T1,'string'));

t2=str2double(get(handles.T2,'string'));

t3=str2double(get(handles.T3,'string'));

t4=str2double(get(handles.T4,'string'));

Nth=(1-((t4-t1)/(t3-t2)))*100;

set(handles.OUT1,'string',num2str(Nth));

Answer 1

[Walter Roberson]

if all(t3 > [t4, t2]) && all([t1,t2] < t4) && t2 > t1
    Nth = (1-((t4-t1)/(t3-t2)))*100;
    set(handles.OUT1,'string',num2str(Nth));
else
    handles.OUT1.String = 'Invalid inputs';
end

[Bedivere Cabahug]

your god given angel :) thank you so much