To begin, let's create a new project in NetBeans. I'm going to call mine Variables, and this time we'll allow NetBeans to create the main class for us so that we can get to coding as quickly as possible. We need to delete all the comments that are created automatically by NetBeans when we create our new project, just to keep everything as readable as possible, then we'll be good to go:

The first computers were little more than calculators, and Java, of course, retains this functionality. For example, Java can evaluate 1+1, which will evaluate to 2, of course. However, Java is pretty complicated and designed to do a lot of different things, so we need to provide context to our commands. Here, we tell Java that we'd like it to print the result of 1+1:

package variables; 
 
public class Variables { 
 
    public static void main(String...

When we're simply counting and manipulating whole objects, integers are fantastic. However, sometimes we need to deal with numbers in a more mathematical sense, and we need a data type that will allow us to express ideas that are not entirely whole numbers. Floating-point numbers, or floats, are a Java primitive type that allow us to express numbers that have decimal points and fractions. In this section, we'll modify some float and integer variables side by side to see how they are similar and different.

Let's create a new Java project (you know the drill by now) and call it FloatingPointNumbers. Let's start by declaring two variables: one integer (iNumber) and one float (fNumber). As we know, once we've declared these variables, we're free to modify and assign values to them in our Java program later. This time, let me show...

A good portion of our time on any software development project is going to be spent teaching our program to solve the types of problems it would comes across on a regular basis. As programmers, we too will run into certain problems time and time again. Sometimes, we'll need to code our own solutions to these problems and hopefully save them for later use. However, more often than not, someone has run into these problems before, and if they've made their solution publicly available, one of our options is to leverage their solution for our own gain.

In this section, we'll use the Math class library, which is bundled with the JDK to solve some math problems for us. To start this section, create a brand new NetBeans project (I'm going to name it TheMathLib) and enter the main() function. We're going to write a very simple program. Let...

Programs that manipulate numbers are all well and good, but quite often, we want to be able to work with text and words as well. To help us do this, Java defines the character, or char, the primitive type. Characters are the smallest entity of text that you can work with on a computer. We can think of them to start off with as single letters.

Let's create a new project; we'll call it Characters.java. We'll start our program by simply defining a single character. We'll call it character1 and we'll assign to it the value of uppercase H:

package characters; 
 
public class Characters { 
    public static void main(String[] args) { 
        char character1 = 'H'; 
    } 
} 

Just as we have to use some extra syntax when defining a floating-point number explicitly, we need some extra syntax when defining a character. To tell Java that...

Let's talk about strings in Java. To begin, create a new NetBeans project, name it StringsInJava, and enter the main() function. Then, declare two variables: a character called c and String called s. Right away, it becomes clear to us that String is a little different. You'll notice that NetBeans did not choose to color code our String keyword with blue, as it would have done if we were declaring a variable of a primitive type:

This is because String, unlike char, is not a primitive type. String is what we call a class. Classes are the backbone of object-oriented programming. Just as we can declare variables of a primitive type, we can also declare variables of a class, which are called instances. In our program, the variable s is an instance of the String class. Unlike variables of primitive types, instances of a class can contain their own special methodologies...

In this chapter, we explained what variables are and how important they are for creating better programs. We looked at some of the primitive data types of Java, namely int, long, float, char, and double, in detail. We also saw the String class and two of its manipulation methods.

In the next chapter, we'll look at branching statements in Java.