How to set ID's inside for loop

[XiviC 03]

I'm makng calculator and i want to make buttons and sets it's ID using
for loop for quick coding but my problem is when i click the button nothing's happen.
I use the CreateWindowEx inside the for loop and ID's.


#define ID_btn0 1001
#define ID_btn1 1002
#define ID_btn2 1003
#define ID_btn3 1004
#define ID_btn4 1005
#define ID_btn5 1006
#define ID_btn6 1007
#define ID_btn7 1008
#define ID_btn8 1009
#define ID_btn9 1010


int WControl(HWND hwnd, HINSTANCE hInst) {
int i, IDs = 0, r = 0;
int x = 10, y = 40, width = 40, height = 30;
for(i = 0; i < 10; i++) {
if(r == 0) { //do nothing. } else if(r == 3) {
/* when r equal to 3 set value of x by 10 and increment the value of y by 40 */
/*for it's new y location */
x = 10; y += 40; r = 0;
//big width for number zero
if(i == 9) {
width = 90;
} }
else if(r < 3) {
//each time r is < 3 increment the value of x by 50 x += 50;
}
CreateWindowEx(0, "button", "9 to 0", WS_CHILD | WS_VISIBLE, x, y, width, height, hwnd, (HMENU)ID_btn9 - IDs, hInst, 0);
r++;
IDs++;
}
return 0;
}