稍稍改了下
// palette
void palette(){
    double x;
    double y = 300;
    double x1 = 400;
    double x2 = 400;
    COLORREF color;
    HDC hDC = ::GetDC(NULL);
    color = ::GetPixel(hDC, 400, 300);
    if((GetBValue(color))<100){
        while( (::GetPixel(hDC, x1, 300))<100){
            x1++;
        }
        while( (::GetPixel(hDC, x2, 300))<100){
            x2--;
        }
            x=(x1)/2+(x2)/2;
    while((::GetPixel(hDC, x, y))){
        y++;
    }}
     mouse_event(MOUSEEVENTF_ABSOLUTE | MOUSEEVENTF_MOVE, (x-1), (y-1), 0, 0);
    return;
}
编译通过，运行直接报错（变量x未定义）