Prog3

1
Prog3
2
Good OO Programming

• ADT
• Data and operations on that data
• Data Encapsulation
• Data and its operations bundled together
• Data Hiding
• Hiding the details of the implementation from
  the user

3
FixedPoint Class

• Data
• private int value, qVal
• Constructors
• public FixedPoint(double x, int q)
• public FixedPoint( FixedPoint x )
• private FixedPoint( int v, int q )
• Operations
• public String toString()
• public boolean equals ( Object x )
• public double toDouble()
• public FixedPoint plus ( FixedPoint p, int
  resultQ )
• public FixedPoint times ( FixedPoint p, int
  resultQ )
• private FixedPoint changeQ ( int newQ )

4

• private FixedPoint( int v, int q )
• public FixedPoint( FixedPoint p )
• private FixedPoint changeQ ( int newQ )
• int qDiff newQ - qVal
• if( qDiff gt 0 )
• return new FixedPoint( value ltlt qDiff,
  newQ )
• else if( qDiff lt 0 )
• return new FixedPoint( value gtgt -qDiff,
  newQ )
• else
• return new FixedPoint( value, qVal )
• //return new FixedPoint( this )

5

• public class FixedPoint
• private int value, qVal
• ...
• private FixedPoint changeQ ( int newQ )
• ...
• _at_Override
• public boolean equals (Object p)
• if ( p instanceof FixedPoint )
  FixedPoint x (FixedPoint)p return (
  value x.changeQ(qVal).value
• this.changeQ(x.qVal).value
  x.value ) return false

6

• public class FixedPoint
• private int value, qVal
• ...
• private FixedPoint( int v, int q )
• private FixedPoint changeQ ( int newQ )
• ...
• public FixedPoint plus ( FixedPoint p, int
  resultQ )
• FixedPoint p1 changeQ(resultQ)
• FixedPoint p2 p.changeQ(resultQ)
• return new FixedPoint( p1.value p2.value,
  resultQ )

7

• public class FixedPoint
• private int value, qVal
• ...
• private FixedPoint( int v, int q )
• private FixedPoint changeQ ( int newQ )
• ...
• public FixedPoint plus ( FixedPoint p, int
  resultQ )
• return new FixedPoint(changeQ(resultQ).value
  
• p.changeQ(resultQ).val
  ue,
• resultQ )

8
Style

• Class comment
• Method (including constructor) comment
• Comment style
• Indentation
• Tabs
• Line too long