Java version determines whether two lines are intersecting

/**
* Determine whether two lines intersection a line segment 1 start coordinate B line 1 end coordinate C line 2 start coordinate D line 2 end coordinate intersection Coordinate
* Reutrn intersection: 0: two lines parallel-1: not parallel and not intersection 1: two lines Intersection
*/
Public int segintersect (point a, point B, point C, point D ){
Point intersection = new point ();

If (math. ABS (B. gety ()-. gety () + math. ABS (B. getx ()-. getx () + math. ABS (D. gety ()-C. gety ())
+ Math. Abs (D. getx ()-C. getx () = 0 ){
If (C. getx ()-A. getx () + (C. Gety ()-A. Gety () = 0 ){
System. Out. println ("ABCD is the same point! ");
} Else {
System. Out. println ("AB is a vertex, CD is a vertex, And the AC is different! ");
}
Return 0;
}

If (math. Abs (B. Gety ()-A. Gety () + math. Abs (B. getx ()-A. getx () = 0 ){
If (. getx ()-D. getx () * (C. gety ()-D. gety ()-(. gety ()-D. gety () * (C. getx ()-D. getx () = 0 ){
System. Out. println ("A, B is a point, and it is on the CD line segment! ");
} Else {
System. Out. println ("A, B is a point and is not on the CD line segment! ");
}
Return 0;
}
If (math. Abs (D. Gety ()-C. Gety () + math. Abs (D. getx ()-C. getx () = 0 ){
If (D. getx ()-B. getx () * (. gety ()-B. gety ()-(D. gety ()-B. gety () * (. getx ()-B. getx () = 0 ){
System. Out. println ("C, D is a point, and on the AB Line Segment! ");
} Else {
System. Out. println ("C, D is a point and is not on the AB Line Segment! ");
}
Return 0;
}

If (B. gety ()-. gety () * (C. getx ()-D. getx ()-(B. getx ()-. getx () * (C. gety ()-D. gety () = 0 ){
// System. Out. println ("parallel line segments, no intersection point! ");
Return 0;
}

Intersection
. Setx (B. getx ()-A. getx () * (C. getx ()-D. getx ())
* (C. Gety ()-A. Gety ()-C. getx ()
* (B. getx ()-A. getx () * (C. Gety ()-D. Gety () +
. Getx () * (B. Gety ()-A. Gety () * (C. getx ()-D. getx ()))
/(B. Gety ()-A. Gety () * (C. getx ()-D. getx ()-(B
. Getx ()-A. getx () * (C. Gety ()-D. Gety ())));
Intersection
. Sety (B. Gety ()-A. Gety () * (C. Gety ()-D. Gety ())
* (C. getx ()-A. getx ()-C. Gety ()
* (B. Gety ()-A. Gety () * (C. getx ()-D. getx () +
. Gety () * (B. getx ()-A. getx () * (C. Gety ()-D. Gety ()))
/(B. getx ()-A. getx () * (C. Gety ()-D. Gety ()-(B
. Gety ()-A. Gety () * (C. getx ()-D. getx ())));

If (intersection. getx ()-A. getx () * (intersection. getx ()-B. getx () <= 0
& (Intersection. getx ()-C. getx ())
* (Intersection. getx ()-D. getx () <= 0
& (Intersection. Gety ()-A. Gety ())
* (Intersection. Gety ()-B. Gety () <= 0
& (Intersection. Gety ()-C. Gety ())
* (Intersection. Gety ()-D. Gety () <= 0 ){

If (. getx () = C. getx () &. gety () = C. gety () | (. getx () = D. getx () &. gety () = D. gety ())
| (B. getx () = C. getx () & B. gety () = C. gety () | (B. getx () = D. getx () & B. gety () = D. gety ())){

System. Out. println ("intersection of line segments on the endpoint ");
Return 2;

} Else {
System. Out. println ("line segments intersect with points (" + intersection. getx () + ","
+ Intersection. Gety () + ")! ");
Return 1; // 'intersection
}

} Else {
// System. Out. println ("the line segments intersect with virtual intersections (" + intersection. getx () + ","
// + Intersection. Gety () + ")! ");
Return-1; // 'intersection but not on the Line Segment
}

}