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Thread: Explicit Conversion?

  1. #1
    Java kindergarten chronoz13's Avatar
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    Default Explicit Conversion?

    the book that im reading says
    "" + <number>
    << "this is the easy way to convert a numerical value to STRING"?

    assuiming that the variable number is an integer.

    is it what they called explicit conversion?
    Last edited by chronoz13; November 11th, 2009 at 05:17 AM.


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    Super Moderator helloworld922's Avatar
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    Default Re: Explicit Conversion?

    No, that's an implicit conversion (technically, it's not a cast at all in this case, see the reason below). An explicit conversion is one you specifically tell Java to do:

    int a = 5;
    String b = (String) a; // explicit

    Note: because of the funny implementation of Strings in Java, this cast here will fail (the compiler will complain).

    Reason: Java normally doesn't allow operator overloading. However, the + has been over-ridden for Strings to mean concatenation. The String concatenation method is able to take any primitive data type and convert it to a string equivalent value. However, because String is not a primitive data type, you cannot explicitly tell Java you want to cast an int to a String and vise versa.
    Last edited by helloworld922; November 11th, 2009 at 10:22 AM.

  3. #3
    Java kindergarten chronoz13's Avatar
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    Default Re: Explicit Conversion?

    oh sorry thats what im trying to imply, i just misinterpret the difference between "implicit" and " explicit" conversion..

    yah yah, thats what i want to ask.. "implicit" haha,, ,

    i thought this was "explicit"
    [CODE] "" + number[\CODE]
    so this is the "implicit"

    anyway, so thats how the java manipulate strings, and tnx for the knowledge about "concatenating", every time i concatenate a primitive type i thougt that it still have value (i mean its data type) as it is when you declared it..

    like the code above, i thought that the variable "number" is still the data type as when you declared it , but when you concatenate it with strings. it will become string too(and that is "implicit") hehe, thought it was "explicit" ,

    i just understood it reversely..

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    Super Moderator helloworld922's Avatar
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    Default Re: Explicit Conversion?

    concatenation doesn't really apply to primitives... It means "adding to the end of".

    So:
    "Hello" + " world"
    is the same as
    "Hello".concat(" world");

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