USER-DEFINED METHODS - Java Programming: From Problem Analysis to Program Design - page 431

int numberOfCourses;

double avg1; //average for a course in group 1
double avg2; //average for a course in group 2

double avgGroup1;
double avgGroup2;

Scanner group1 =
new Scanner( new FileReader("group1.txt"));
Scanner group2 =
new Scanner( new FileReader("group2.txt"));

PrintWriter outfile = new PrintWriter("student.out");

Next, we discuss the methods calculateAverage and printResult . Then, we
will put the method main together.

This method calculates the average for a course. Because the input is stored in a file
and the input file is opened in the method main , we must pass the variable associated
with the input file to this method. Furthermore, after calculating the course average,
this method must pass the course average to the method main . Therefore, this
method has one parameter.
To find the course average, we must first find the sum of all the scores for the
course and the number of students who took the course; we then divide the sum
by the number of students. Thus, we need a variable to find the sum of the scores,
a variable to find the number of students, a variable to find the course average, and
a variable to read and store a score. Of course, we must initialize the variables
to zero to find the sum and the number of students.

Method
calculate
Average

7

In the previous discussion of data manipulation, we identified four variables for the
method calculateAverage :

Local
Variables
(Method
calculate
Average)

double totalScore; //to store the sum of scores
int numberOfStudents; //to store the number of students
int score; //to read and store a course score

double courseAvg; //to store the course average

The preceding discussion translates into the following algorithm for the method
calculateAverage :
a. Declare the variables.
b. Initialize totalScore to 0.0 .
c. Initialize numberOfStudents to 0 .
d. Get the (next) course score.