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Welcome to my Java page. Here you will find some very simple
Java source code done by me as part of my Computer Science course. This is not meant to be a tutorial on Java, the page is here to give you some examples from which you can learn from. It is very simple code (getting more complicated as you go down the page) with very little error checking but it may help you to figure out how some of the basics of Java. Be aware that some of the files have the same names but they are actually different so make sure you download all the files for that particular program. I have written a Java MIDP game called Atomic which you may be interested in looking at. |
Simple programs | Slightly more complicated | Java interfaces | Data structures | MVC | GUI | Code writing interview questions
Simple Programs
Program Name |
Description |
Further Technical Info |
| DayFromDate.java | Program To Calculate the day from the date using Zeller's congruence. | Calls external classes. [requires NeilClass.java] |
| DaysInMonth.java | Type in the number of days in the month and on which day the month starts and it will produce a calender for that month. | Get's input, uses For loops and If statements. |
| EmailSurname.java | Type in an email address such as bill.gates@microsoft.com and it will extract the 'gates' bit of it | Uses indexOf and substring to extract the Surname. |
| Factorial.java | Produces factorials by using the switch statement. | Demonstrates the use of the switch statement. |
| LeapYear.java | Prints out a list of which years are leap years. | Demonstrated 'for' and 'if, else' constructs. |
| ListAverage.java | Inputs a list of numbers and then gives you the average of them. | Uses While, For and If constructs. |
| Midnight.java | Type in the number of minutes past midnight and this will tell you what the time is | Simple input & modula arithmetic. |
| NewtonRaphson.java NewtonRaphsonClass.java |
Calculates the square root of a number using the Newton Raphson formula. | Calls internal methods & external classes. [requires NeilClass.java] |
| ReverseAlt.java | Reverses the letters of alternate words. | Demonstrated string tokeniser |
| SimilarWords.java | Compares two words and tells you how many of the letters are different. | Inputs two strings and compares them using charAt. |
| Stamps.java | Type in the weight of your parcel and it will tell you how much you need to spend on stamps. | Simple If constructs |
| TempChart.java | Outputs a chart of temperatures in Celcius and Fahrenheit. | Uses a for loop to produce the chart. |
| WordOrder.java | Type in two words and the program will tell in which order they come. | Uses compareTo and StringTokeniser |
Slightly More Complicated Programs
The non linked programs are coming soon.
Most of these need NeilClass.java
Program Name |
Description |
Further Technical Info |
| BinomialCoefficient.java needs GetBiClass.java |
Calculated The Binomial Coefficient of two numbers. | Does some error checking with pre & post conditions. |
| FileCopy.java | Copies and displays the contents of a file. | Copies the data into a byte array before outputing it to the destination file. As it copies the data one byte at a time it can be a bit slow. Contains no error checking. |
| FileCopyEC.java | Same as above. | Same as above but contains the propper error checking code. |
| FileDisplay.java | Displays the contents of a file. | Contains no error checking. |
| FileEncrypt.java | Encrypts a file | Uses very simple XOR encryption. Contains no error checking. |
| GCD.java needs GCDClass.java |
Calculates the GCD using a recursive functions. | Does some error checking with pre & post conditions. |
| NewtonRaphson.java needs NewtonRaphsonClass.java |
Calculates the square root of a number using the Newton Raphson formula. | Like the previous Newton Raphson program but does some error checking with pre & post conditions. |
| Nought.java | A very simple noughts & crosses game. | Coded very craply I have to admit but I didn't have much time to do it in. Needs NeilClass.java. |
| Connect4.java | A simple Connect 4 game. | Adapted from the Noughts & Crosses Java code but it is coded much better. It is also a far superior game. |
| CarGoatSim.java | Simulates and solves the Car & Goats quiz problem. | Creates random numbers. |
Java Interfaces
Some programs which are the same as above
but which use Interfaces plus some new ones.
Download Java Interface Files
(4kb)
Program Name |
Description |
Further Technical Info |
| Bermuda Triangle PositionMain.java PositionImpl.java Position.java |
Uses a formula to work out if co-ordinates are in the Bermuda triangle & prints out a grid showing the triangle. | Demonstrates Interfaces |
| Binomial.java needs GetBiClass.java & BinaryInterface.java |
Calculated The Binomial Coefficient of two numbers. | Does some error checking with pre & post conditions. |
| GCD.java needs GCDClass.java & GCDInterface.java |
Calculates the GCD using a recursive functions. | Does some error checking with pre & post conditions. |
| NewtonRaphson.java needs NewtonRaphsonClass.java & NewtonInterface.java |
Calculates the square root of a number using the Newton Raphson formula. | Like the previous Newton Raphson program but does some error checking with pre & post conditions. |
| Binary.java BinaryClass.java BinaryInterface.java |
Binary Simulator. Converts from denary to binary & back. Adds 2 binary numbers and works out the 2's complement of a binary number. | Uses Interfaces and arrays. |
Data Structures
Program Name |
Description |
Further Technical Info |
| SyntaxCheck.java StackImpl.java Stack.java |
Syntax Checker - You input an expression such as ({hello})[] and it will tell you if the "()", "{}" and "[]" match. | Demonstrates how to create and use a stack. |
| ReadList.java Position.java PositionImpl.java Pos.dat |
Flight Planner, reads positions from a file into an Array List and then allows you to move through them, view them and change the values. | Shows how to use Java's Array List structure. |
| FigureProg.java Figure.java Circle.java Rectangle.java data.dat |
Reads objects from a file and puts them in a Hash Set. | Uses the Hash Set data structure and demonstrates its iterator. |
| Flight Planner TranslateFlight.java Position.java PositionImpl.java Flight.dat Points.dat |
This program reads a load of Positions into a HashMap. It then reads a flight plan from a second file and retrieves the Positions for each of the destinations from the HashSet | Uses a Hash Map and shows how to get specific items from it. |
| Patience CardTest.java Pack.java PackImpl.java Patience.java PlayingCard.java PlayingCardImpl.java NeilClass.java |
Patience Game, Uses a generic Playing Card and Pack object to create a simple card game. The ADT is designed to be as generic as possible so any card game could be created using it. | Uses List Array Structure, shows how to create a simple to use generic ADT. |
| Linked List DoubleClient.java DoubleNode.java DoubleList.java |
Custom written Linked List implementation and a program to demonstrate it. |
MVC
Program Name |
Description |
Further Technical Info |
| PersonArrayQueueProg.java Queue.java ArrayQueue.java OutputQueue.java Person.java PersonImpl.java Date.java DateImpl.java |
Lets you add people to a population and remove them. | Demonstrates the MVC viewer system. However this example does not demonstrate it very well as it only uses one viewer. |
Graphical User Interfaces
These programs need JDK 1.2
Program Name |
Description |
Further Technical Info |
| Calc.java CalcWindow.java |
Add or subtract two numbers from a simple GUI. | Sets up a GUI and gets input from it. |
| Bermuda Triangle GUI PositionMain.java PersonInputBox.java PositionForm.java.java PositionFormJFrame.java PositionFormProg.java PositionInputBox.java Position.java PositionImpl.java |
Inputs the Bermuda Triangle's Co-ordinates from 3 pop up dialogue boxes and then displays a simple representation of the triangle. | Sets up a GUI and gets input from it. |
Code writing interview questions
If you want to go a bit more advanced here are some links to C++ interview code writing questions. The C++ code linked here is fairly similar to what the Java source code would look like. It wouldn't be hard to convert it into Java code if you needed to.- Triangle identification - how to identify the type of triangle when given the side lengths.
- Reverse the words in a sentence
- Pick the 5th from last element in a singly linked list
- Reverse a linked list
- Dijkstra's algorithm - for finding the shortest route between two points in a graph
- Select 100 random values from a stream / linked list - an unusual question, but fun to think about.
- QuickSort implementation
Getting the Java examples to work
- Compile the .java file into a .class file by typing "javac whatever.java".
- Then run it by typing "java whatever"
If the programs need NeilClass.java then this must be in the same directory as the Java program which is being compiled. These programs were written using emacs on UNIX.
Related Links
- PhotoStamper - simple command line utility written in Java that takes a JPEG photo and then adds a date/time stamp to the photo. Includes Java source.
- Atomic - Atomic is a J2ME (mobile version of Java) game where you have to take over the board with your atoms. Playable on most mobile phones.
- Reverse Engineering Project - tool written in Java to convert Java source / class files into UML.
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