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2010-06-01T05:18:59Z

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в 17:44, 31 мая 2010

2010-05-31T17:44:27Z

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== An Overview of Java Statements ==

<OL><LI>In programming, a statement is an instruction to do something.</LI><LI>It controls the sequence of execution of a program.</LI><LI>In Java, a statement is terminated with a semicolon and multiple statements can be written on a single line.</LI></OL>



<source lang="java">
x = y + 1; z = y + 2;</source>



== Combining both statements into one ==



<source lang="java">
class Animal {
public Animal(String aType) {
type = aType;
}
public String toString() {
return "This is a " + type;
}
private String type;
}
public class MainClass {
public static void main(String[] a) {
System.out.println(new Animal("a").getClass().getName()); // Output the
// class name
}
}</source>



<pre class=codeResult>Animal</pre>

== Declaring and defining multiple variables in a single statement ==

A comma separates each variable.



<source lang="java">
public class MainClass{
public static void main(String[] arg){
long a = 999999999L, b = 100000000L;
int c = 0, d = 0;

System.out.println(a);
System.out.println(b);
System.out.println(c);
System.out.println(d);
}
}</source>



<pre class=codeResult>999999999
100000000
0
0</pre>

== Expressions ==

Some expressions can be made statements by terminating them with a semicolon.
For example, x++ is an expression.
However, this is a statement:



<source lang="java">
x++;</source>



Statements can be grouped in a block.
A block is a sequence of the following programming elements within braces:
<OL><LI>statements</LI><LI>local class declarations</LI><LI>local variable declaration statements</LI></OL>

== How to write multiple assignments in a single statement ==



<source lang="java">
public class MainClass{
public static void main(String[] argv){
int a, b, c;

a = b = c = 777;

System.out.println(a);
System.out.println(b);
System.out.println(c);
}
}</source>



<pre class=codeResult>777
777
777</pre>

== Label a statement block ==

<OL><LI>A statement and a statement block can be labeled.</LI><LI>Label names follow the same rule as Java identifiers and are terminated with a colon.</LI></OL>



<source lang="java">
public class MainClass {
public static void main(String[] args) {
int x = 0, y = 0;
sectionA: x = y + 1;
}
}</source>



Label statement can be referenced by the break and continue statements.

== Spreading a single declaration over several lines ==



<source lang="java">
public class MainClass {
public static void main(String[] arg) {
int a = 0, // comment for a
b = 0, // comment for b
c = 0, // comment for c
d = 0;
System.out.println(a);
System.out.println(b);
System.out.println(c);
System.out.println(d);
}
}</source>



== Statement Blocks ==

<OL><LI>You can have a block of statements enclosed between braces.</LI><LI>If the value of expression is true, all the statements enclosed in the block will be executed.</LI><LI>Without the braces, the code no longer has a statement block.</LI></OL>



<source lang="java">
public class MainClass {
public static void main(String[] arg) {
int a = 0;
if (a == 0) {
System.out.println("in the block");
System.out.println("in the block");
}
}
}</source>



<pre class=codeResult>in the block
in the block</pre>

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Admin: 1 версия

в 17:44, 31 мая 2010