Java Reference
In-Depth Information
Self-Test Exercises
(continued)
25. Write a method defi nition for a method with the following heading. The
method is to be added to the class
GradeBook
in Display 6.18 .
/**
Changes the grade for student number studentNumber on quiz
number quizNumber to newGrade.
*/
public void
changeGrade(
int
studentNumber,
int
quizNumber,
int
newGrade))
26. Write a method defi nition for a method with the following heading. The
method is to be added to the class
GradeBook
in Display 6.18 .
/**
Returns an array with the average quiz score for each student.
*/
public double
[] getStudentAverages( )
27. Write a method defi nition for a method with the following heading. The
method is to be added to the class
GradeBook
in Display 6.18 .
/**
Returns an array with the average score for each quiz.
*/
public double
[] getQuizAverages( )
Chapter Summary
•
An
array
can be used to store and manipulate a collection of data that is all of the
same type.
•
The
indexed variables
of an array can be used just like any other variables of the
base
type
of the array.
•
Arrays are objects that are created with
new
just like the class objects we discussed
before this chapter (although there is a slight difference in the syntax used).
•
A
for
loop is a good way to step through the elements of an array and perform some
program action on each indexed variable.
•
The most common programming error made when using arrays is to attempt to
access a nonexistent array index. Always check the first and last iterations of a loop
that manipulates an array to make sure it does not use an index that is illegally small
or illegally large.
