java

1
???? ????? ????? ? java

• ????? ????? ????? ??? ?'

2
????? ????? ????? ??? ???

• ?????? ????, ??????, ????? 3.
• ????? ???? ????? ?? ????? ????? ,????? - ?????
  ???, ????????.
• ????? ?????? ????, ?????, ?????, ????? ??????
  ?????? Point, ??????? ??.
• ???? ????? ??? ????? ???????? ?????? ??????
  ?????.
• ????? ????, ???? PointContainer

3
????? ????? ????? - ????????

• ??? ??????? ?? ??? ????, ?? ???? ????.
• ?????? ?????, ??????? ?????, ??????.
• ????? ?? ?"??" ??"???".
• ???? ?????? ??????????? ?????? ???? ????.
• ????? ?????? ?????, ?????? ?????, ??????, ????..
• ??????? ?????? ????? ??? ????? ????????.

4
?????? ??????? ??? Point

• ??? ??? ????? (?????) ????.
• ???? ?????? ???? ??????, ???? ?????
• ???? ??????

class Point int _x, _y // data member!!
boolean same(Point p) return (p._x _x
p._y_y) void print() S.O.P.(_x,
_y) // class Point
5
?????? ??????? ??? Point

• ????? ????? ?????? ?????.
• ????? ????? , ???? ?? ?????..

class TextPoint public static void
main(String a) Point p1 new Point() //
constructor! Point p2 new Point(p1._x,
p1._y) p1._x 3 p1._y2 p1.print() //
3,2 boolean b p1.same(p2) // true
6
?????? ??????? ??? Point

• ???? ???? ??????, ?????? ????????.
• Copy constructor ????? "????"

class Point int _x, _y // data member!!
Point (int x, int y) _xx _yy
Point(Point p) _xp._x _yp._y // class
Point
7
?????? ??????? ??? Point

• ???? ???? ?? ????? public \ private
• ?????? ???? ????? ????? ????.

public class Point private int _x, _y //
data member!! public Point (int x, int y)
_xx _yy public int x() return _x
public int y() return _y // class Point
8
?????? ??????? ??? Point

• ????? ?????? - ???? ??????.

class TextPoint public static void
main(String a) Point p1 new Point(2,3)
//constructor! Point p2 new Point(p1)
p1._x 5 // ERROR (its private).
s.o.p(p1.x()) // o.k. public boolean b
p1.same(p2) // true
9
?????? ??????? ??? Point

• ????? ?????? ?? ????? ????, ????.
• ????? ?? ?????? (?????) ?? ?????.
• ????? ?? ?????.
• ????? ?????? ?? ????

class Point double distance(Point p)
double dx x()-p.x(), dy _y-p._y //
x() , _x return Math.sqrt(dxdx dydy) //
class Point
10
?????? ????? ??? Circle

• ?????? ?????? ???? ??????
• ???? ??
• ?????? ???, ????, ???? ?????.
• ???? ?????? String toString()
• ?????? ?????? ??????? ?? ????????, ????? ????
  ????? ?? ???????? System.out.print ?? ???????.

11
?????? ????? ??? Circle

• ?????? ?????? ???? ??????
• ???? ????? ??????.
• ????, copy constructor.

class Circle private Point _center
private double _radius public Circle(Point
cen, double rad) _center new
Point(cen) _radius rad // copy
constructor
12
?????? ????? ??? Circle

• ????? ?????
• ???, ????.
• toString
• ??? ????? ?????

class Circle public double area()
return Math.PI_radiud_radius public
String toString() return Circle
cen_center rad _darius public
boolean contains(Point p) // // class
Circle
13
????? ??????? Point, Circle
class TestCP public static void
main(String a) Point p1new
Point(5,6), p2new Point(1,3) double d
p1.distance(p2) // 5.0 Circle c1
new Circle (p1,4) boolean in
c1.contains(p2) // false
14
????? ????? ????? - ????

• ??? ?????? ??????? ?????.
• ????? ????, ?????, ?????, ??????.
• ????? toString(), ????? ?? ?????????.
• ???? ?? ?????? Point ps new Point4
• ????? ??? ?????? ??????? ?????? ???
• (data members)
• ??? ?? ????? ? java ????? ?? ????? ??? ?????
  (???? ?????? ????? ???? ?????? Jcreator).

15
?????? ??? ???? ????????

• this ???? ?????, ?????? ????? ???? ?????.
• ???? ??????? ???? (?? ???????), ?????? ????????
  ????? ????? (????? ?????) ??? ????? ????? ???
  ????? ???? ?? ????????, ????? ?? ???? this.
• ???? ????? ?? this ?? ??????? ???? ?? ??????.
• ?????? this ???? ???? ??? ???? ????? ?? ??????
  ???.

16
????? ????????? ??????? this

• ??? ????? ???? ????? ????????? ????.
• this ????? ?? ??? ???? ?????? ?? ?????.
• Point pnew Point(5,6)
• Circle cnew Circle(p,4)
• Circle c2

17
???? ?????? ???? ?? ??????

• ??? ????? ?? ?? ????? ?? ???????
• ?????? ?? ???? (Container)
• ????? ?????.
• ?????, ????? ??????, ????? ????????.
• ???? ??????, ???? ?????.
• ?????? ????.
• ??????.
• ????.

18
???? ?????? ???? ?? ??????

• public class PointContainer
• // data members
• public static final int INIT_SIZE10 // init
  size.
• private int _sp0 // stack pointer
  
• private Point _points // the point array
• / Constructors creates a empty set /
• public PointContainer()
• _sp0
• _points new PointINIT_SIZE

19
???? ?????? ???? ?? ??????

• public int size() return _sp
• public void add (Point p)
• if (p ! null)
• if(_sp_points.length) rescale(10) // RESCALE
• _points_sp new Point(p) // deep copy
  semantic.
• _sp
• public Point at(int p)
• if (pgt0 pltsize()) return _pointsp
• return null // no need for else!

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???? ?????? ???? ?? ??????

• / private methodes /
• private void rescale(int t)
• Point tmp new Point_spt
• for(int i0ilt_spi) tmpi _pointsi
• _points tmp

21
???? ?????? ???? ?? ??????

• ????? ??????
• ?????? ????.
• ????? (copy constructor)
• ????? ?? ???? ?????.
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• ?????, (???? ???? ??? ????)
• ???? ????, (????? ?? ??? ?????? ???????).

22
?? ????? ????

• ????? ? Object Oriented
• ??????? (?????? ?????)
• ?????, ????.
• ???? ?? ??????
• ???? ?????? ??????? ???? ?? ????? ?????.
• ?? ???? ????
• ??? ??????, ???? ?? ????? ??????.
• ????? ?? ???????? ???? ?? ??????.