Java Programming

else
printf("NOT TEN");
a = 100;

}

The above code looks perfectly normal. If a is 10, then print "TEN" otherwise print "NOT TEN" and set a to 100.

With certain languages (C/C++ and Java included), that code would not quite work as described. The way the code is indented can make someone believe that it is doing something else.

According to the way C/C++ and Java would interpret the above code, it should look more like this:


void doStuff(int a) {

if(a == 10) {
printf("TEN");

}else {
printf("NOT TEN");

}

a = 100;

}

Which means that no matter what, a would be set to 100 at the end of the function call, which is not how the indentation made it look in the original example.

Keep in mind that both examples are identical in function if interpreted by a C/C++ or Java style compiler.

It can be either

if (cond1) { if (cond2) stmt1; else stmt2; }

or

if (cond1) { if (cond2) stmt1; } else stmt2;

It is important to rembember that the compiler does not know which of those you meant, so it choose the first interpretation: the dangling else belongs to the inner if.

In C#, data types can be categorised as

1. Value Types.
2. Reference Types.

Value Types

Variables defined from Value Types store values. Copying one value type caribale tp another, doesn't affect the priginal vraible.

They can be further categorised into: -

1) structs: - They can be numeric (int, float, decimal), bool, user-defined structs.

2) Enumerations: - They consist of a set of named constants. By default the first enumerator has value=0.

Reference Types

These objects store references to the actual data. These can be categorised into: -

1) Classes: -- They encapsulate data and its functionality into a single entity called OBJECT.

2) Interfaces: - These are used to declare the signatures, blurprints of methods, delegates and events.

3) Delegates: - These contain the addresses/references to a method.

For more information refer to related links.

Depends on what you want the project to teach.

What project list would be complete without the standard Hello World project? Learn the creation of classes, use of the main method, and standard output.

Projects which deal with calculating mathematical concepts are common. Factorials, GCD, LCM, area of geometric shapes, etc. Also, simple string manipulation projects, like printing out a string of a firstname-lastname pair, then switching them. Use arrays or other data structures to process many of these calculations and store the answers.

As above, except have the functions calculated by input given through the command line by the user.

Specific example: Have the user enter any number of integers as command line arguments to have their factorials calculated. If one of the inputs is not an integer, print an error message. If one of the inputs would result in a factorial that would be too large (greater than 20 for a long integer), print an error message. Otherwise print the factorial of the number.

Other points of this exercise are to validate input and (possibly) use a recursive solution for a problem.

As above, except take input via standard input.

Specific example: Have the user enter numbers (either integer or floating point). Keep track of all unique numbers entered until the user enters non-numeric data. Once done accepting input: print all numbers in order from least to greatest, print the sum/mean/median/mode of the numbers, and print how many numbers entered were integers and how many were floating point.

Other points of this exercise are to consider various types of data structures, sorting data, parsing data, and filtering data.

As above, except take input from files and direct output into files.

Specific example: Have the user specify two file names on the command line. The first will be our input file, the second will be our output file. The program should exit with an error message if: there are an incorrect number of command line arguments, both are the same file name, or either specifies a file that does not exist. Otherwise, the first file will contain a series of lines of text. Each line will have three parts, separated by a space character. Each line will contain one part containing entirely numbers, one part containing entirely lowercase letters, and one part containing entirely uppercase letters. The parts of each line will be in a different order. The program will parse each line and write them to output in the following format: "(number part,lowercase part,uppercase part)".

Other points of this exercise are to learn exception handling (must-have with file I/O), data type recognition, and output formatting.

As above, except make it look pretty.

Specific example: Have the user enter three values into a text box, then press a button. The program will interpret the three values as the length, width, and height of a cuboid (3D rectangle). The button will cause another window to pop up and display information about the cuboid: volume, surface area of each of the three distinct sides, total surface area, and distance from one corner to the opposite corner. Finally, (and most importantly?) ensure that the program exits when the user closes the window.

For extra difficulty, implement the following: Do not allow the three input boxes to record any non-numeric characters. Make the popup window block input to the original window until it is closed. Use a layout which will ensure that the input window will both allow for resizing and space out the components evenly whenever the window size changes.

Other points of this exercise are sub-concepts of GUI building: component layout, event handling, and "graceful" exits from a program.

As above, except read and write input between networked computers.

Specific example: This will require two different programs running on remote machines. Have the user enter a string in the date format: "MM/DD/YYYY". Ensure that the date is in the past. Continue asking for input until a valid date is entered. The program should then connect to a remote computer and send the date string over. At this point, the program running on the remote computer will analyze the string and determine what day of the week that date was. The remote program will then take today's date and figure out when the next day (tomorrow or later) will be that will be the same day of the week. It will send this back to the original program. The original program will print this value out and both programs will exit.

By "reflection" I mean having to do with a program knowing information about itself. Have the program read information from itself or even have it modify some of its methods and execute itself.

Specific example: Have the user input the name of a class. The program should display information about each method in the class in the format: "access_modifier return_type method_name(parameters) [throws exception_types]"

Another (harder) specific example: Have the user input any valid code, a single line at a time. When the user specifies, execute the code and display the results (if any).

If you didn't figure it out already, just take the simple calculations from the first section and incorporate them into any new concept you want to teach.

Depending on whether you are a Web Designer or Web Developer. Many will wonder, What is the main difference between those two?

First off, there is a difference between a web designer and a web developer. Those of us fortunate enough to posses both sets of skills are the lucky ones who get to say "Yes" when asked if they can do a project. No matter what the project is. Then there's the OTHER group. Those who SAY they can do what you need.

Web Designer: A designer designs the style, colors and images on a website, and about 90% of the time they can also do simple HTML (the language which make a website actually work, where you can click on links to see other pages, etc...)

Web Developer: A developer can program a website to DO things, not just show pages of information. For example, perhaps you want to have a feature where the user / customer can search for stores by zip code or browse items in a catalog, have a shopping cart, sign up for a newsletter, login to the site with a password, have a database of items to download, etc...

So the basic difference between design and development is that one provides you with simple pages (About Us, Company History, Contact Us, etc...) these are called static sites. The other allows your site to actually do something, not just show information. These are called dynamic sites or a web application.

Dynamic sites typically cost more because they require more time, expertise and resources to develop.

These days, there is a huge demand for Flash (animated, perhaps with sounds, etc.) sites. These sites typically cost more because they require a level of artistic AND programming skills. Many designers will buy a template (a pre-made design) and just change the logo, name of the company and information and sell you the site. While this is a cheap and quick solution, you run the risk of having your site look like OTHER sites that have purchased that same template, thus reducing your credibility. Often times people want Flash websites without understanding that they don't NEED them and they can often be negative to your image. Flash is great for many websites, but awful for some.

Sorry about long response however experienced Web Developer can earn up to 70-100k/year or up to $50/hr on contract.

Swapnil Amin

A java method is a series of statements that perform some repeated task. Instead of writing 10 lines of code we can put those ten lines in a method and just call it in one line. It is like a shortcut.

For example if we had to repeatedly output a header such as: System.out.println("Feral Production");

System.out.println("For all your Forest Videos");

System.out.println("427 Blackbutt Way");

System.out.println("Chaelundi Forest");

System.out.println("NSW 2473");

System.out.println("Australia");

We could put it all in a method like this: public static void printHeader(){

System.out.println("Feral Production");

System.out.println("For all your Forest Videos");

System.out.println("427 Blackbutt Way");

System.out.println("Chaelundi Forest");

System.out.println("NSW 2473");

System.out.println("Australia");

}

And to call it we simply write: printHeader();

And it will print out:

Feral Productions

For all your Forest Videos

427 Blackbutt Way

Chaelundi Forest

NSW 2473

Australia

Java methods provide us with features to pass arguments to it and also return values from it.

#

Static Methods Can:

• Access only static variables
• Invoke other static methods only

Static Methods cannot:

• Access Instance variables
• Invoke instance or non-static methods