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Problem with arrays

 
Greenhorn
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Hello!
Found this question at the site: http://www.examsonline.com and I find it hard to understand why answer D is correct since answer A is wrong. Can anyone please explain to me?
QWhat are valid ways of declaring and initializing arrays? Select all that apply.
A int [ ] arr = new int [5] {1, 2, 3, 4, 5};
Bint arr [5] = new int [ ] {1, 2, 3, 4, 5};
Cint arr [ ] [ ] = new int [5] [ ] {1, 2, 3, 4, 5};
Dint arr [ ] [ ] = new int [5] [5] {{1, 2, 3, 4, 5},
{1, 2, 3, 4, 5}};
Eint [ ] arr [ ] = new int [25];
The correct answers is C, D, E according to the site I mentioned above.
And by the way, I�ve got one more question to you:
I assume that the declaration
int arr [][] = //some code;
means the same as
int[] arr[]= //some code;
Is that correct??
/Linda
 
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9
Scala Java
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Linda,
you bring up some really good points, I am sure you will get more answers. I didnt realize answer d was correct. and i am real curious about answer e. I think both are probably ok.
your assumption is absolutely correct:
int[][]b = int[]b[] = int b[][]
and you can add as many spaces as you want anywhere.
 
Greenhorn
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Hi,
I think in the above case only option E is fine. When you
initialize during declaration, the compiler accepts only when the number of elements in the RHS is blank.
So it would be right to say
int [ ] arr = new int[] {1, 2, 3, 4, 5} but not
int [ ] arr = new int[5] {1, 2, 3, 4, 5};
Same holds good for D also. Pls correct me if I am wrong.
I tried the above with JDK1.2.2
Thanks
MKBala...
 
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Hi,
I have tried all the examples given above and the only one that works is A. According to my JDK1.2 compiler your can never specify a size when initializing using anonymous arrays. Therefore, B, C, and D are not correct. JDK1.2 gives error messages for each of those cases.
Answer E is not correct because you are trying to assign an int[] to an int[][]. JDK1.2 compiler will not let that happen!
Make sure the test you have is for JDK1.2 and not JDK1.1. I don't think it will make a difference, but you never know ...
Regards,
Manfred.
 
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Linda,
None of them above were correct
A int [ ] arr = new int [5] {1, 2, 3, 4, 5}; --> Incorrect
Reason: {1, 2, 3, 4, 5} creates an array and initializes its elements to the specified values.
Corrected form int [ ] arr = new int [] {1, 2, 3, 4, 5};
B int arr [5] = new int [ ] {1, 2, 3, 4, 5}; --> Incorrect
Reason: arr [5] should not have dimention in it.
Corrected form int [ ] arr = new int [] {1, 2, 3, 4, 5};
C int arr [ ] [ ] = new int [5] [ ] {1, 2, 3, 4, 5}; --> Incorrect
Reason: This is a two dimensional array. Initialization should be different
Corrected form int arr [ ] [ ] = new int [ ] [ ] {{1, 2, 3, 4, 5},{1,2,3,4,5}};
D int arr [ ] [ ] = new int [5] [5] {{1, 2, 3, 4, 5},
{1, 2, 3, 4, 5}}; -->Incorrect
Reason: If you define size don't initialize with {{1, 2, 3, 4, 5},
{1, 2, 3, 4, 5}};
Corrected form : Either remove size or initialization
int arr [ ] [ ] = new int [] []{{1, 2, 3, 4, 5}, {1, 2, 3, 4, 5}};
or
int arr [ ] [ ] = new int [5] [5];
E int [ ] arr [ ] = new int [25]; --> Incorrect
Reason: In compatible declaration
Corrected form:
int [ ] arr = new int [25];
or
int arr [ ] = new int [25]

[This message has been edited by venu gopal (edited January 19, 2001).]
 
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Hi Folks !
I am with venu Gopal. None of the answers are correct
 
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Hi , Linda , Welcome to Javaranch.
Proper Names are Now Required. Linda javaranch has got naming policy which everybody has to strictly follow. Please Re register yourself with proper last name & enjoy sharing wealth of knowledge.
Your Friendly Bartender
Shailesh.

[This message has been edited by shailesh sonavadekar (edited January 19, 2001).]
 
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