网上找到了一份代码，本机无法使用，请教原因：

#include <Windows.h>
#include <cstdio>
using namespace std;
int main()
{
	HWND WIN;
	WIN = FindWindowA(NULL, "微信 - 文件传输助手");
	TCHAR text[256] = TEXT("c++ test");
	for (int i = 0; i < lstrlen(text); i++)
		SendMessage(WIN, WM_IME_CHAR, text[i], 0);
	Sleep(50);
	SendMessage(WIN, WM_KEYDOWN, VK_RETURN, 0);
	return 0;
}