Java array declaration creation and initialization

This article has covered several aspects of Java arrays, including the declaration, creation, and initialization of Java arrays, and the corresponding code.
One dimensional array declaration : type var []; Or type [] var.

You cannot declare an array by specifying its length (the number of elements in the array),

The keyword new is used in Java to create array objects, Format for : array name = type of new array element [number of array elements]

Example: testnew.java:

Program code:

public class TestNew 
{ 
   public static void main(String args[]) { 
     int[] s ; 
     int i ; 
     s = new int[5] ; 
     for(i = 0 ; i < 5 ; i++) { 
       s[i] = i ; 
     } 
     for(i = 4 ; i >= 0 ; i--) { 
       System.out.println("" + s[i]) ; 
     } 
   }  
} 

Initialization:

1. Dynamic initialization: the array definition is conducted separately from the operations of allocating space and assigning values to the array;
2. Static initialization: allocate space and assign values to array elements while defining Numbers;
3. Default initialization: an array is a reference type whose elements correspond to the member variables of the class, so after the array is allocated space, each element is also initialized by the hermit according to the rules of the member variables.
Example:

Testd. Java (dynamic) :

Program code:

public class TestD 
{ 
   public static void main(String args[]) { 
     int a[] ; 
     a = new int[3] ; 
     a[0] = 0 ; 
     a[1] = 1 ; 
     a[2] = 2 ; 
     Date days[] ; 
     days = new Date[3] ; 
     days[0] = new Date(2008,4,5) ; 
     days[1] = new Date(2008,2,31) ; 
     days[2] = new Date(2008,4,4) ; 
   } 
} 
 
class Date 
{ 
   int year,month,day ; 
   Date(int year ,int month ,int day) { 
     this.year = year ; 
     this.month = month ; 
     this.day = day ; 
   } 
} 
 

Tests. Java (static) :

Program code:

public class TestS   
{   
   public static void main(String args[]) {   
     int a[] = {0,1,2} ;   
     Time times [] = {new Time(19,42,42),new Time(1,23,54),new Time(5,3,2)} ;   
   }   
}   
 
class Time   
{   
   int hour,min,sec ;   
   Time(int hour ,int min ,int sec) {   
     this.hour = hour ;   
     this.min = min ;   
     this.sec = sec ;   
   }   
}  

Testdefault.java (default) :

Program code:

public class TestDefault   
{   
   public static void main(String args[]) {   
     int a [] = new int [5] ;   
     System.out.println("" + a[3]) ;   
   }   
}  

The above is about Java array declaration, creation, initialization of the example, I hope you can understand, to help you learn.