GUI Edit TextBox: display 2 values separated by a space

I have 2 textbox in my GUI. User needs to enter a range in TextBox_1 (e.g.: 1 5) and second TextBox shows the output with some simple Maths calculation. My current script:

function edit1_Callback(hObject, eventdata, handles)
A = get(handles.edit1,'String');
B = str2num(A{:});
C=2+B;
set(handles.edit2,'String',C);

However, second textbox disappears from GUI when I run this script. May I know which part of the script was written wrongly? Thanks.

Answer 1

[Walter Roberson]

set(handles.edit2,'String', num2str(C));