Cmpt 225

Simon Fraser University
School of Computing Science

Cmpt 225 - Lab #1

Getting to know the fundamentals of Java

Objectives

Our objectives in this Lab #1 is to become familiar with the fundamentals of Java. Specifically, we will learn...

how to create a small Java application.
how to create classes and their members: data fields and method (constructor, getter (or accessor), setter (or mutator), etc. )
how to create a class test driver to test our class.
how to compile and execute our files.
more specially, as we are solving the problem described in this lab, we will gain familiarity with:

primitives data types such as int, boolean, char, double, float, etc.
constant ( final keyword)
enum
mathematical operators such as +, ++, /, etc.
mathematical expressions
boolean operators such as &&, ||, etc.
boolean expressions
if and switch constructs
for (2 variations), while and do while loop constructs
main method (static)
basic (keyboard/console) input/output mechanisms (I/O streams)

package java.io
StringBuffer and StringTokenizer classes
format output such as DecimalFormat in the java.text.DecimalFormat package

packages (how to use them) and import directive
typecast (implicit and explicit)
wrapper classes and autoboxing
String class
array
void and value-returning method
default constructor (constructor without parameters)
parameterized constructors
varags
static members of a class
how to instantiate objects, i.e., how to use the operator new
how to use reference variables
how objects are destroyed in Java (garbage collector)

Problem Statement

In this lab we are to develop a Student Registration and Grades application which is to provide the following functionality:

Store information about students such as

last name
first name
whether or not a student is a Canadian
a student's grades for all the courses taken.

Calculate and display the overall average (average of all grades obtained by one student).
Compute and display the application fee for each student.

Requirements

We need to take the following into account when we develop our application:

User must be able to enter first and last names of a student, her/his nationality and the grade for each of the courses a student has taken. In this lab, we shall not record the courses taken, simply the awarded grades.
Grades are given in integral percentage (e.g. 78%), therefore they can only be integers from 0 to 100.
The application fee is calculated as follows:

For Canadian students with overall average >= 85%, the application fee is Fee1.
For International students with overall average >= 85%, the application fee is Fee2.
For any students with overall average < 85%, the application fee is Fee3.
The application fees are as follows:

Fee1 is $30,
Fee2 is $45, and
Fee3 is $70

Use arrays whenever we need to store many elements of the same data type.
We must store the size of the grades array as a constant since all students will have the same number of grades and we shall not expand the array of grades.

Suggestions

Design and Implementation

When creating our classes, apply encapsulation as we would when we create C++ classes. This is to say, our application (client code) must not be able to access the data fields of our classes directly. We will need to create appropriate methods in order to allow the client code to access these data fields and modify their content.
Remember: there are no pointers and pointer arithmetic in Java.
Make sure we have included all necessary packages at the top of our files.

Remember: we cannot define variables outside the scope of a class. All data must reside inside our class.
We don't have to separate the interface of a class (*.h file) from its implementation (*.cc) as we would do in C++.
There are no unsigned data types in Java.
The type char uses the Unicode characters, not the ASCII code as in C++.
Size of the array don't have to be a compile-time constant, as in C++.
Since Java has an automatic garbage collection, there are no destructors in Java.

Compilation

Information about our compiler can be found at: SFU CMPT Course Central Software: Java Documentation
We can compile several files in a variety of ways. Here are a few:

javac *.java

javac <name of file containing the main method with its ".java" extension>

javac <name of all java files with their ".java" extension>

If the java file containing our main method is called LAB1.java, we compile it using the following command

javac LAB1.java

After performing this command our executable file is named LAB1.class

To run our application, we use the following command:

java LAB1

Resources

The first thing we will need to do is investigate and read about the topics listed above in the Objectives section . Below are partial lists of books and web sites you may wish to look at in order to perform your investigation.

List of books:

Java from the Beginning (2nd Edition) (International Computer Science Series) - by Jan Skansholm
Beginning Java Objects: From Concepts to Code - by Jacquie Barker
Tutorial for JBuilder - by Y. Daniel Liang
Beginning J2EE 1.4 - by James L. Weaver, Kevin Mukhar, James P. Crume, Ron Phillips

List of web sites:

As stated, the above lists are not exhaustive, therefore feel free to add to them the Java books and web sites you find useful. Also, feel free to send these (books and URL's) to the instructor so that they can be added to this lab and to our course web site.

Anne Lavergne, Irina Pekerskaya and Zhi Hao Lin - May 2004 to January 2005 - Last Revision date September 2006