Different ways of Array creation

[Ravindranath Chowdary]

Hi friends,

What is the difference between these two array creations:
int[] array = {1,3,4,5}; //This works fine.

int[] array;
array = {1,3,4,5};//This gives an error as "illegal start of expression".
Even though the array is declared in the first line why this is giving an error.
Can any one explain the reason for this.

Thanks,
Ravindra.

[Urs Waefler]

Hi

Me too I would like to know the reason. I try an approach.

int[] array1;
array1 = {1,3,4,5};

The first line tells, there is an array of int called array1. There is no memory allocation.
If there is a semicolon at the end of a line, it is an expression. The second line has a semicolon at the end. The compiler tells: illegal start of expression.

Who can continue to develop the thoughts?

Regards
Urs

[Svend Rost]

Hi,

in this statement: int[] array = {1,3,4,5}; you declare and construct an array with the size of 5.

In this statement: int[] array you declare an integer array.
This statement: array = {1,3,4,5}, expects that the right hand side
(the {1, ..} part) is a construction of the array.

/Svend Rost

[Campbell Ritchie]

Try this instead:-

import static java.lang.System.*;
 
public class ArrayConstructionTest
{
private int[] array;

public static void main(String[] args)
{
try
{
new ArrayConstructionTest(args);
}//end try
catch(NumberFormatException nfe)
{
out.printf("One of the arguments wasn't a proper integer number:%n%s", nfe.getMessage());
}//end catch
}//end main

public ArrayConstructionTest(String[] args)
{
array = new int[]{1, 2, 3};
array = new int[args.length];
for(int i = 0; i < array.length; i++)
array[i] = Integer.parseInt(args[i]);
out.printf("Finished%n%n");
}//end constructor
}//end class
//end file

That compiles and runs nicely

[fred rosenberger]

int[] array = {1,3,4,5};

The real question is not why the second way DOESN'T work, but why the first way DOES work.

This is a convenient shortcut the fine people at Sun gave us. I believe it is a leftover from C. Very few objects have shortcuts to create them - arrays and Strings are the only two i can think of off the top of my head.
[ March 21, 2007: Message edited by: Fred Rosenberger ]

[James A Anderson]

Originally posted by Svend Rost:
Hi,

in this statement: int[] array = {1,3,4,5}; you declare and construct an array with the size of 5.

/Svend Rost

Svend,

Why does this contruct an array with the size of 5? Why wouldn't it create an array with the size of 4, since 4 elements are specified?
[ March 22, 2007: Message edited by: James A Anderson ]

[fred rosenberger]

methinks Svend just made a typo...

[Anupam Sinha]

Very few objects have shortcuts to create them - arrays and Strings are the only two i can think of off the top of my head.

and with 1.5 the wrapper classes.