C++ operator overloading

This is a discussion on C++ operator overloading within the C++ Programming forums, part of the General Programming Boards category; can we ask ....... Operator overloading is also called the redesigning of language....

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    Thumbs up C++ operator overloading

    can we ask ....... Operator overloading is also called the redesigning of language.

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    (?<!re)tired Mario F.'s Avatar
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    Not really, in my opinion. Mostly because operator overloading must have an argument of class type. You can't overload operators for built-in types.

    Also, you can't alter precedence and associativity rules and you lose control of short-circuit evaluation.

    Macros could perhaps be seen as a way to "redesign" a language. But operator overloading, not really.
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    Originally Posted by brewbuck:
    Reimplementing a large system in another language to get a 25% performance boost is nonsense. It would be cheaper to just get a computer which is 25% faster.

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    You could overload minus to do addition, or plus to do subtraction for your class, but I wouldn't call that "redesigning of language" but rather "being stupid".

    A more logical unusual redefined operator is if you overload '<' and '>' to do something besides comparison. In most cases that would still be poor design in most cases.
    It is too clear and so it is hard to see.
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    Operator overloading is essentially a different way of writing a function.

    It's usually used when the normal operators won't work without defining some special behavior, such as adding two objects together.

    Say you want to "add" two shapes together. You can overload '+' and define what it means to combine the shapes, or you can write a function.

    IMHO - 99% of the time, it's better to write a function, because when you read (or edit) someone else's code, you'll see the operator and you might forget that it's overloaded.

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    I agree with DougDbug, I see the two similarly, and often when people write overloaded operators it causes more hassle then its worth.

    That is not to say they have no place, but if you do use them comment them well so you know whats happening.

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    Just Lurking Dave_Sinkula's Avatar
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    7. It is easier to write an incorrect program than understand a correct one.
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    The superhaterodyne twomers's Avatar
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    Well, I don't think there is any need to do any excess operator overloading. Eg, for a string, the + operator is essential, but there is no need for a * one, why multiply two strings? However, if there is something you want to do, and you could use an operator for it, I would make a function for it rather than using an operator which may be somewhat ... confusing.

    Eg, if I had a string class, and I wanted to get rid of every instance of a sub string in it, I could use the - operator, or I suppose I could use the / one. However, they are both somewhat ambiguous, so I would think that to create a function to de-substring the string would be a better idea.

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    (?<!re)tired Mario F.'s Avatar
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    Overloading STL classes operators seems to me a bad idea, overall. And some operators in particular (< and == come to mind) would be particularly insiduous.
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    Originally Posted by brewbuck:
    Reimplementing a large system in another language to get a 25% performance boost is nonsense. It would be cheaper to just get a computer which is 25% faster.

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    I should add, some opperators, such as '!', ',', and unairy '&' should never be overloaded.
    It is too clear and so it is hard to see.
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    Devil's Advocate SlyMaelstrom's Avatar
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    Quote Originally Posted by Mario F.
    Overloading STL classes operators seems to me a bad idea, overall. And some operators in particular (< and == come to mind) would be particularly insiduous.
    That depends on the type of class your overloading for. Obviously the string class overloads those operators, but they do it in a logical way. Making a + operator subtract in your class or any other kind of illogical use would be insidious, but I think all operators available to be overloaded should be(assuming a need to do so) overloaded, as long as it's logical and responsible.
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    Cat without Hat CornedBee's Avatar
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    You could overload + to do substraction. You could also write a function called "print" that reads a value from the console. It's exactly the same: misleading function names.
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    Devil's Advocate SlyMaelstrom's Avatar
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    Quote Originally Posted by CornedBee
    You could overload + to do substraction.
    I said insidious, not impossible.
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    Cat without Hat CornedBee's Avatar
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    I was mostly referring to King Mir's first post.
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    semi-colon generator ChaosEngine's Avatar
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    Quote Originally Posted by King Mir
    I should add, some opperators, such as '!', ',', and unairy '&' should never be overloaded.
    never say never. Boost.shared_ptr overloads operator '!' to allow you to test the value of the contained pointer.

    which means you can do
    Code:
    boost::shared_ptr x(new Something());
    
    // later
    
    if (!x)
    {
        cout << "OMG, someone reset my pointer! you b@stards!!"
    }
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    The superhaterodyne twomers's Avatar
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    >> I should add, some opperators, such as '!', ',', and unairy '&' should never be overloaded.

    Yeah, I meant to ask you about that. Why should they never be overloaded?

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