我想创建一个程序，我每按一次键，它就发送一次键击。这个程序有问题，因为即使在我停止按键后，它仍继续发送键击。
例如：如果按下"向上"，它将继续按向上，直到我按下另一个键。
你能帮我一下吗？
谢谢

int main()
{
    // This structure will be used to create the keyboard
    // input event.
    INPUT ip;

    while(1)
    {
             if (GetAsyncKeyState(VK_UP) < 0)
          {
            INPUT ip;
            ip.type = INPUT_KEYBOARD;
            ip.ki.time = 0;
            ip.ki.dwExtraInfo = 0;          
            ip.ki.wVk = 0x26; // virtual-key code for the "UP arrow" key
            ip.ki.dwFlags = 0; // 0 for key press
            SendInput(1, &ip, sizeof(INPUT));
          }

          if (GetAsyncKeyState(VK_DOWN) < 0)
          {
            INPUT ip;
            ip.type = INPUT_KEYBOARD;
            ip.ki.time = 0;
            ip.ki.dwExtraInfo = 0;          
            ip.ki.wVk = 0x28; // virtual-key code for the "UP arrow" key
            ip.ki.dwFlags = 0; // 0 for key press
            SendInput(1, &ip, sizeof(INPUT));

          }

           if (GetAsyncKeyState(VK_RIGHT) < 0)
          {
            INPUT ip;
            ip.type = INPUT_KEYBOARD;
            ip.ki.time = 0;
            ip.ki.wVk = 0;
            ip.ki.dwExtraInfo = 0;          
            ip.ki.wVk = 0x27; // virtual-key code for the "UP arrow" key
            ip.ki.dwFlags = 0; // 0 for key press
            SendInput(1, &ip, sizeof(INPUT));

          }

          if (GetAsyncKeyState(VK_LEFT) < 0)
          {
            INPUT ip;
            ip.type = INPUT_KEYBOARD;
            ip.ki.time = 0;
            ip.ki.dwExtraInfo = 0;          
            ip.ki.wVk = 0x25; // virtual-key code for the "UP arrow" key
            ip.ki.dwFlags = 0; // 0 for key press
            SendInput(1, &ip, sizeof(INPUT));

          }

    }

    // Exit normally
    return 0;
}