Admin: 1 версия

2010-06-01T05:06:38Z

1 версия

в 17:44, 31 мая 2010

2010-05-31T17:44:27Z

Новая страница

== Demonstrate lifetime of a variable ==



<source lang="java">
public class MainClass {
public static void main(String args[]) {
int x;
for (x = 0; x < 3; x++) {
int y = -1; // y is initialized each time block is entered
System.out.println("y is: " + y); // this always prints -1
y = 100;
System.out.println("y is now: " + y);
}
}
}</source>



<pre class=codeResult>y is: -1
y is now: 100
y is: -1
y is now: 100
y is: -1
y is now: 100</pre>

== helloMessage variable is declared as a local variable: ==



<source lang="java">
public class MainClass
{
public static void main(String[] args)
{
String helloMessage;
helloMessage = "Hello, World!";
System.out.println(helloMessage);
}
}</source>



== shows the proper way to declare a class variable named helloMessage ==



<source lang="java">
public class MainClass
{
static String helloMessage;
public static void main(String[] args)
{
helloMessage = "Hello, World!";
System.out.println(helloMessage);
}
}</source>



== Variable Dynamic Initialization ==



<source lang="java">
public class MainClass {
public static void main(String args[]) {
double a = 3.0, b = 4.0;
// c is dynamically initialized
double c = Math.sqrt(a * a + b * b);
System.out.println("Hypotenuse is " + c);
}
}</source>



<pre class=codeResult>Hypotenuse is 5.0</pre>

== Variables ==

<p>Variables are data placeholders.
There are two data types in Java:</p>
<OL><LI>Reference types provides a reference to an object.</LI><LI>Primitive types hold a primitive.</LI></OL>

== You don"t have to place class variable declarations at the beginning of a class. ==



<source lang="java">
public class MainClass
{
public static void main(String[] args)
{
helloMessage = "Hello, World!";
System.out.println(helloMessage);
}
static String helloMessage;
}</source>

← Предыдущая	Версия 05:06, 1 июня 2010
(нет различий)

Java Tutorial/Language/Variables - История изменений

Admin: 1 версия

в 17:44, 31 мая 2010