Simulate a key press for a window

#define VK_ENTER 0x0D  // 0x0D is a hex value for the key Enter
#define VK_E 0x45  // Same as above
#define VK_K 0x4B  // Same as above
#define VK_L 0x4C  // Same as above
#define VK_Y 0x59  // Same as above

void main()
{
HWND Notepad = FindWindow(TEXT("Notepad"), NULL);  // Looks for the window titled Notepad
HWND edit = FindWindowEx(Notepad, NULL, TEXT("Edit"), NULL);  // In the window there is a class called Edit
PostMessage(edit, WM_KEYDOWN, VK_K, 1);  // Posts a message to the edit window "K"
PostMessage(edit, WM_KEYDOWN, VK_Y, 1);  // "Y"
PostMessage(edit, WM_KEYDOWN, VK_L, 1);  // "L"
PostMessage(edit, WM_KEYDOWN, VK_E, 1);  // "E"
PostMessage(edit, WM_KEYDOWN, VK_ENTER, 1);   // Sends enter
}