Java Coding Samples

Java Coding Samples

Various Java programs to illustrate various concepts

• A Hello World! Java program.
• Calling Methods. A sample of how to call methods in the same class.
• For loop. A simple example of using for loops to calculate factorial. Uses the built in int data type so only good to 13!
• Enhanced for loop
• Value Parameters: An example that shows the behavior of value parameters. In Java all parameters are passed by value. 
• String Example. A few brief examples of String manipulations.
• BinaryConverter. A program with examples of various Java syntax that converts a base 10 int to base 2 String.
• PrimeEx A program with various approaches to determine if an int is prime or not. Used to demonstrate Java syntax. You need the Stopwatch class, a non standard Java class, as well.
• Pointers as Value parameters
• Array Examples
• 2D array Example. A simplified version of filtering a picture represented by ints.
• 2D array example. Very simple version of the Conway's Game of Life.
• Getting input from Keyboard with Scanner class
• Reading ints from file with Scanner class
• Writing ints to file
• Connecting to and reading from a web page.
• Program to create ASCII frequency table from file and url. Demonstration of try / catch blocks. The CIA 2008 Factbook may be downloaded from Project Gutenberg.
• IntListVer1 First version of the IntList class developed in class. Developing class to illustrate various class design and implementation issues in Java.
• IntListTesterVer1
• IntListVer2 Added default add method, equals method, and toString methods. Includes versions of toString using String concatenation and StringBuffer to illustarte performance differences.
• IntListTesterVer2
• IntListVer3. Added insert and remove methods.
• SortedIntList. Inherits from InListVer3 to create a SortedIntList. Class is "broken" because random insertions still allowed.
• GenericList. Altered the list to store anything, not just ints.
• Die class. A class that models a playing die.
• DemoClass: This illustrates some of the more confusing concepts in class syntax and mechanics such as constructors, static vs. instance methods, and method overloading. 
• Stopwatch class. A class for measuring how long it takes for a program to run.
  • Documentation for Stopwatch class.
• Create a Set. A method that using polymorphism to create a set from an array.
• Recursion examples. Includes examples on finding space taken up by files in a directory including all files in all subdirectories, recursive factorial, recursive power, recursive Fibonacci numbers, and a simple knapsack problem.
• Eight Queens example. Code to find a a solution to an N queens problem. Note the queensAreSafe method has not been completed.
• Airlines example. Determine if airlines can be moved from airline to another based on network of airline partners. Here is a sample input file.
• Minesweeper. Another example of recursion from the game minesweeper.
• GenericListVersion2. Changed the GenericList class so that it implements the Iterable interface in order to demonstrate how to implement an iterator using an inner class.
• GenericListVersion3. Changed GenericList so it is generic based on Java generics syntax instead of relying on Object.
• ListNode. A singly linked node class used to build linked lists
• IList. A simple list interface
• LinkedList. Similar to the LinkedList developed in class. Does not contain all the methods you would expect of a LinkedList. Also implements the iterator remove method in O(N) time. An O(1) time remove method is possible.
• UnsortedHashSet - An unsorted set that uses a hashtable with closed address hashing to store values. Currently only the add method is implemented.
• UnsortedSetTest - A method to compare Java's TreeSet and HashSet to the BianrySearchTree, UnsortedSet, and UnsortedHashSet classes developed in class. Note you need a lot of other files for this to work.
• SimpleWordCount - Program demonstrating use of a map to count the frequency of words in a file.
• WordCount - Program  that compares counting words in files using an ArrayList and a Map.