Examples of smaller Java programs that do various interesting things.

codingSamples.md 6.6KB

Java Coding Samples

Various Java programs to illustrate various concepts from an old CS course at UTexas.edu.

  • 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.

  • 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.