计算几何-Dot-Vector

 1 struct D{
 2   db x,y;
 3   D(db x=0.0,db y=0.0):x(x),y(y){}
 4 };
 5 typedef D V;
 6 bl op<(D A,D B){return A.x<B.x||(A.x==B.x&&A.y<B.y);}
 7 V op+(V A,V B){return V(A.x+B.x,A.y+B.y);}
 8 V op-(V A,V B){return V(A.x-B.x,A.y-B.y);}
 9 V op*(V A,db N){return V(A.x*N,A.y*N);}
10 V op/(V A,db N){return V(A.x/N,A.y/N);}

int main(){
   A[1]=V(1,2);
   cout<<A[1].x<<" "<<A[1].y<<endl;
   cout<<A[2].x<<" "<<A[2].y<<endl;
   A[2].y+=1.0,cout<<"add"<<endl;
   A[3]=A[1]+A[2];
   cout<<A[3].x<<" "<<A[3].y<<endl<<endl;
   sort(A+1,A+3+1);
   for(int i=1;i<=3;i++)cout<<A[i].x<<" "<<A[i].y<<endl;
   return 0;
}

1 2
0 0
add
1 3

0 1
1 2
1 3