C++ 打開記事本 並寫入文件 （能打開可是寫不進去求解答）

#include <iostream> #include <windows.h> #include <fstream> int main () {   HWND hwnd; hwnd = ::FindWindow ("Notepad","無標題-記事本"); if (hwnd == NULL)  {  ::ShellExecute(hwnd,"open","a.txt",NULL,NULL,SW_SHOWNORMAL);  Sleep(1000); char str[12] = "1";  ::SendMessage (hwnd, WM_SETTEXT, 0,(LPARAM)str); //向EDIT寫入文字 } }