Now that you have Eclipse up and running, let's take a look at some programming basics.

The most core fundamentals of programming in any language are variables. Variables are like spaces in a parking garage; they are addresses the computer sets aside to store a value. Like parking spaces, there are different kinds of variables for different data types. If you try to store the wrong type of data in a variable, you'll get an error! Though it's a bit of an over-simplification, let's think of four types of variables for now, and how to use them.

1. String - a string variable is for storing words, letters, sentences, or anything that's not a number. You can put a number here, but it won't be the actual number, it will just be the letter of that number. Confused? Think of it as a piece of paper. If you write 5 on the paper, it doesn't mean you have five of something; it just means you have a paper with 5 written on it. Strings are going to be quite important, so get used to using them.

2. Int - an int is any number without a decimal point. You can add them, subtract them, multiply them, or do a number of other things with them. However, be careful when dividing ints! Because they can't store decimal points, often you'll get a lot of rounding errors. For dividing, it's best to use doubles.

3. Doubles - a number with a decimal point. It can also store larger numbers than ints. If you're not sure what to use, best go with a double.

4. Boolean - can be either true or false. It's also known as a "flag" variable, because it acts like a flag - it's either up or down, telling to computer to do something (or not do something.)

So, now that you get the basics of variables, let's learn how to declare them. To declare a variable means to create the space in the parking garage (your computer program) where you want to store that value. Remember, Java is case sensative, so make sure everything is lower case, unless you're typing "String." The first S in string is always capitalized. Let's try making a simple program. Open the test program we started in the last lesson, and add these lines after the line you typed.

String myString;
myString = "Hey people! This is my string! I'm gonna type in it like nobody's business!";
System.out.println(myString);

Do you see what we did thar? Using the Print command, we just created a variable, put a value in it, and printed out that value. Let's try something with numbers next.

int aNumber;
int anotherNumber;
int sumOfNumbers;
aNumber = 5;
anotherNumber = 13;
sumOfNumbers = (aNumber*anotherNumber);
System.out.println(sumOfNumbers);

Remember, if I had done anything with decimal places, I would have wanted to use a double rather than an int.

Don't worry too much about booleans for now; you'll understand them better once we get to loops in another lesson or two. Now that you know how to use variables and how to print output (remember, use the System.out.println(); command with whatever you want to print in between the parantheses. If it's not a variable, make sure to put it in quotation marks!) you can go ahead and make a few simple project! Go ahead and experiment - that's the best way to learn!

Oh, one more thing. Make sure you put a semi-colon at the end of every line of code; that's just the way Java works! If you don't add one, it'll keep looking for the end of the line and stall or break. Don't worry; you can't damage your computer if you forget one, but your program probably won't work correctly!