Two-dimensional geometric program head calculation (Template)

  # Include  <  Iostream  >  
# Include  <  Cmath  >  
  Using     Namespace  STD;
  Const    Double  Epoints  =  1e  -  9  ;
  Int  SGN (  Double  A ){
  Return  (  >  Epoints)  -  ( <     -  Epoints );
}
  Const     Double  Pointi  =  ACOs (  -  1.0  );
  Struct  Point {
  Double  X, Y;
Point ( Double  Xx  =  0  ,  Double  YY  =  0  ){
X  =  XX; y  =  YY;
}
  Bool     Operator    =  (  Const  Point  &  A)  Const  {
  Return  SGN (x  -  A. X)  =     0     &&  SGN (Y -  A. Y)  =     0  ;
}
  Bool     Operator     ! =  (  Const  Point  &  A)  Const  {
 Return  SGN (x  -  A. X)  ! =     0     |  SGN (Y  -  A. Y)  ! =     0  ;
}
  Bool    Operator     <  (  Const  Point  &  A)  Const  {
  Return  SGN (Y  -  A. Y)  <     0    |  SGN (Y  -  A. Y)  =     0     &&  SGN (x  -  A. X)  <     0  ;
}

Point  Operator    +  (  Const  Point  &  A)  Const  {
  Return  Point (x  +  A. X, Y  +  A. Y );
}
Point  Operator    -  (  Const  Point  &  A)  Const  {
  Return  Point (x  -  A. X, Y  -  A. Y );
}
Point  Operator     ^ (  Const     Double     &  A)  Const  {
  Return  Point (x  *  A, y  *  A );
}
  Double    Operator     ^  (  Const  Point  &  A)  Const  {  //  Point product  
    Return  X  *  A. x +  Y  *  A. Y;
}
  Double     Operator     *  (  Const  Point  &  A)  Const  {  //  Cross Product 
    Return  X  *  A. Y  -  Y  *  A. X;
}

Point trunlen (  Double  A)  Const  {
A  /=  SQRT (x  * X  +  Y  *  Y );
  Return  Point (x  *  A, y  *  A );
}
Point turn_left ()  Const  {
  Return  Point (  - Y, X );
}
Point turn_right ()  Const  {
  Return  Point (Y,  -  X );
}
  Double  Cross (  Const  Point  &  A,  Const  Point  & B)  Const  {  //  Use this as the starting point of the Two-vector Cross Product  
    Return  (A. x  -  X)  *  (B. Y  -  Y)  -  (A. Y  - Y)  *  (B. x  -  X );
}
  Double  DOT (  Const  Point  &  A,  Const  Point  &  B)  Const  { //  Starting from this, the dot product of two vectors  
    Return  (A. x  -  X)  *  (B. x  -  X)  +  (A. Y  -  Y)  *  (B. Y -  Y );
}

  Double  Len2 (){
  Return  X  *  X  +  Y  *  Y;
}
  Double  Len ()
{
  Return  SQRT (len2 ());
}

 Void  Input (){
Scanf (  "  % Lf  "  ,  &  X,  &  Y );
}
  Void  Output ()  Const  {
Printf (  "  % Lf \ n  " , X, y );
}
};
  Int  Main ()
{
  Return     0  ;
} 

 

 

ReferenceACM Wuhan University wiki algorithm Introduction