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Thread: Operators

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    Default Operators

    I could use some help understanding operators. ++, --, +=, -=, *=, /=, and %=. There's something about them that I'm just not getting. I would really appreciate your assistance!


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    Default Re: Operators

    those operators are used just immediate to any variables.
    like
    k++; //k=k+1  but post increment
    ++k; //pre increment the value of k
    similarly all functions as.

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    Default Re: Operators

    something about them that I'm just not getting.
    Please give some details on your problem. Take a look at the tutorial:
    Operators (The Java™ Tutorials > Learning the Java Language > Language Basics)
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Operators

    Thanks for the help. Here is an excerpt from the book I'm reading about operators and which doesn't seem to be explained by the Oracle Java tutorial. This is where my confusion comes from:
    -------------
    int x = 10;
    int y = 20;
    What value is z assigned? The answer is 220. The third assignment increments
    x to 11 and decrements y to 19, but in computing the value of z, it uses the new
    value of x (++x) times the old value of y (y– –), which is 11 times 20, or 220.
    --------------------
    I understand that ++x equals 10+1, which is 11. But I don't understand how --y equals 20. Does --y mean "y minus a minus" or y subtracting (or minus) a minus? That's what is confusing me.

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    Default Re: Operators

    ++ means increment (add 1).
    -- means decrement (subtract 1).

    There's no mathematical intuition or basis for why this is, this is just some idea that the designers decided a long time ago was nifty.

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    Default Re: Operators

    That's what I thought. But how is ++y different from y++? And --y from y--? I ask because in the example above, where int y=20, y-- should mean 20-1 = 19. But the book has the answer as being 20.

    Thanks for answering my newbie questions.

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    Default Re: Operators

    Google postfix operator for lots of discussions about how the operators work.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Operators

    Thanks. I was entering Java and operators, but it never occurred to me to try just try that. Google is giving me a lot of C++ pages, so I'll look at those. Nice indeed! Thanks!

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