Update textbox value from another cpp

[rselvan]

I gotta fetch textbox value from another cpp file.
let's say
one.cpp is having the following code snippet which exactly creates the textbox.

 CreateWindow(TEXT("Edit"), TEXT("test"), WS_CHILD | WS_VISIBLE | WS_BORDER, 100, 20, 140, 20, hWnd, NULL, NULL, NULL); 

I wanna get the output or textbox value which we created above in one.cpp but from another cpp file namely second.cpp.

How would i do that?

[keskiverto]

How do you get the value of that textbox in the "same cpp"?


Lets use a simpler example to clarify things:
A.cpp

#include <iostream>
void foo(int x)
{
  std::cout << x;
}

B.cpp

void foo(int);

int main()
{
  int bar {42};
  return 0;
}

@rselvan: How could the A.cpp use the variable 'bar' from B.cpp?