题目内容：
在下面的横线处填上适当内容，使程序完整。# include
# include
class loc{
private:
float x,y;
public;
loc()
{float x1,float y1；
x=x1;
y=y1;
}
float getx( ){return x;}
float gety( ){return y;}
② float dis(loc&,loc&);
};
float loc::dis(loc&a,loc&b)
{
flost dx=a.x-b.x;
flost dy=a.y-b.y;
return sqrt(dx*dx+dy*dy);
}
void main( )
{
loc pl(3.5,4.5),p2(5.5,6.5);
float d=loc::dis(p1,p2);
cout<<“The distance is”<
}
参考答案：