Well, this is me second tutorial on designing classes with static methods. I'm gonna start you off with a very basic example: the
Math class.
This class has methods that do mathematical calculations...I know...duh. Well, the methods of the
Math class are static, meaning you don't have to instantiate an object to call them. You can simply call them like this.
java
Math.METHOD(parameters_used);
You DON'T have to do this:
java
Math mathObject = new Math();
mathObject.METHOD();
You don't HAVE to do it that way...but you can, but no one I know does that.
Well, we'll make a method that does a very simple calculation. We'll make an
addition() method.
java
class OurMath
{
public static int addition(int a, int 
{
int sum = a + b;
return sum;
}
}
Notice how we declare our
int return type for the method. This makes it so we can assign it to an
int variable in a main method or something.
Also notice the
int variables in the parentheses. These are called 'parameters'. These are what's going to be included in the method when it's called.
It's going to be called like this.
java
int number = OurMath.addition(1, 3);
Well, anyone know what
number is going to equal after that? That's right! Four!
You HAVE to call the method with 2 parameters. If you call it any other way, you're going to going to get a compile error saying something along these lines.
cannot find symbol: method addition(int)static Class VariablesWell, back again to the
Math class. It has 2
double variables, E, and PI.
java
class Math
{
static double E = 2.718...;
static double PI = 3.141596535...;
}
This is how we declare
static (AKA "class") variables. Let's go back to our class...
java
class OurMath
{
static int five = 5;
public static int addition(int a, int
{
int sum = a + b;
return sum;
}
}
Well, now we can access our
five variable through doing this.
java
int ourVariable = OurMath.five;
The main reason of using
static is to make non "object"-ive data or methods.
Hope this tutorial helped anyone that needed it!
Introduction to Designing Classes II, Intro to designing class with static methods.
30 Jul, 2008 - 03:22 PM
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