start a c++(exe) with input from a c++ gui

start a c++(exe) with input from a c++ gui

i just started learning how to program gui in c++ just using dev c++, so
nothing that fancy. with this code:
HWND hWndEdit = CreateWindowEx(
WS_EX_CLIENTEDGE,
TEXT("Edit"),
TEXT("input"),
WS_CHILD | WS_VISIBLE,
100, 20, 140, 20,
hWnd, NULL, NULL, NULL);
i create a text box for input. what i want to do is, get the input somehow
from that text box, and from that start another c++ program with the
command as the input, similar to what would be done on the command line.
if this is not possible, how would i go about getting the text from the
edit field and using it in code? and for other people like me who want to
learn gui from scratch without any kind of builders(like visual studio),
what would you suggest as a proper guide book? or even web tutorials.