I just looked at this SO Post:
However, the Columbia professor's notes does it the way below. See page 9.
Foo foos = new Foo[12] ;
Which way is correct? They seem to say different things.
Particularly, in the notes version there isn't [].
5 Answers
This simply won't compile in Java (because you're assigning a value of an array type to a variable of a the non-array type Foo):
Foo foos = new Foo[12];
it's rejected by javac with the following error (See also: http://ideone.com/0jh9YE):
test.java:5: error: incompatible types
Foo foos = new Foo[12];
To have it compile, declare foo to be of type Foo[] and then just loop over it:
Foo[] foo = new Foo[12]; # <<<<<<<<<
for (int i = 0; i < 12; i += 1) {
foos[i] = new Foo();
}
3 Comments
Erik Kaplun
@JeroenVannevel: amended my answer.
Jon Skeet
@nativist.bill.cutting: Why couldn't you create your own example and verify that it doesn't compile? You say you're not lazy, but how did you try this before asking Eric to do it for you?
Erik Kaplun
@nativist.bill.cutting: so what made you unaccept my answer and accept another one that says the same thing except with no explanation?
Foo[] foos = new Foo[12] ; //declaring array
for(int i=0;i<12;i++){
foos[i] = new Foo(); //initializing the array with foo object
}
answered Oct 5, 2013 at 13:14
Prabhakaran Ramaswamy
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Comments
You can't do this
Foo foos = new Foo[12] ;
change to
Foo[] foos = new Foo[12];
there was a typo in the document on page 9. Also there's a typo on page 10
int[] grades = new int[3]
I would not read the whole document if the typos are on each page.
Comments
Declare by this way.
Foo[] foos = new Foo[12];
Comments
//declaring array of 12 Foo elements in Java8 style
Foo[] foos = Stream.generate(Foo::new).limit(12).toArray(Foo[]::new);
// instead of
Foo[] foos = new Foo[12];
for(int i=0;i<12;i++){
foos[i] = new Foo();
}
newoperation allocates and initializes an array of references to Foo, but it does not create any Foo objects -- the array is initially allnullreferences.)