Java Reference
In-Depth Information
Self-Test Exercises
5. Write a method called
fractionDone
that could be added to the class
DateThirdTry
in Display 4.4 . The method
fractionDone
has a parameter
targetDay
of type
int
(for a day of the month) and returns a value of type
double. The value returned is the value of the
day
instance variable divided by
the
int
parameter
targetDay
. (So it returns the fraction of the time passed so
far this month where the goal is reaching the
targetDay
.) Use fl oating-point
division, not integer division. To get fl oating-point division, copy the value of
the
day
instance variable into a local variable of type
double
and use this local
variable in place of the day instance variable in the division. (You may assume
the parameter
targetDay
is a valid day of the month that is greater than the
value of the
day
instance variable.)
6. Write a method called
advanceYear
that could be added to the class
DateThirdTry
in Display 4.4 . The method
advanceYear
has one parameter
of type
int
. The method
advanceYear
increases the value of the
year
instance
variable by the amount of this one parameter.
7. Suppose we redefi ne the method
setDate
in Display 4.4 to the following:
public void
setDate(
int
newMonth,
int
newDay,
int
newYear)
{
month = monthString(newMonth);
day = newDay;
year = newYear;
System.out.println("Date changed to "
+ newMonth + " " + newDay + ", " + newYear);
}
Indicate all instances of
newMonth
that have their value changed to
6
in the
following invocation (also from Display 4.4 ):
date.setDate(6, 17, year);
8. Is the following a legal method defi nition that could be added to the class
DateThirdTry
in Display 4.4 ?
public void
multiWriteOutput(
int
count)
{
while
(count > 0)
{
writeOutput();
count--;
}
}
9. Consider the defi nition of the method
monthString
in Display 4.4 . Why are
there no
break
statements in the
switch
statement?
