我想设置按下UP时加速，松开UP减速，应该怎么做呢

kingmax0725

RT~

youareeverythin

static float speed =0.0f;
if((GetAsyncKeyState(vk_up) & 0x8000){
speed+=0.1f;
}else{
if(speed<0.0f)speed=0.0f;
else speed-=0.1f;
}