operators... which gets run first?

This is a discussion on operators... which gets run first? within the C++ Programming forums, part of the General Programming Boards category; Code: template< class Type, UInt32 Elements > class MTrArrayType { private: Type Array[Elements]; public: Type& operator [] ( UInt32 Index ...

  1. #1
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    operators... which gets run first?

    Code:
    template< class Type, UInt32 Elements >
    class MTrArrayType
    {
    private:
    	Type Array[Elements];
    
    public:
    	Type& operator [] ( UInt32 Index )
    	{
    		if( Index >= Elements )
    		{
    			cout << "Index out of range: " << Index << "/" << Elements << endl;
    			return Array[0];
    		}
    
    		return Array[Index];
    	}
    
    	operator Type*()
    	{
    		return Array;
    	}
    };
    This is my class. It's an ordinary array class, all it does is check if the index is out of bounds.

    When I put in...

    Code:
    MTrArrayType< int, 3 > MyArray;
    MyArray[1] = 6;
    ..., how do I know which operator function it calls? The one to change it to a Type*, or the one to do the index thing? If it's the one i don't want, how do I change it?

    Thanks!

  2. #2
    & the hat of GPL slaying Thantos's Avatar
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  3. #3
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    Hm. So it was that simple...

    I guess it makes sense.

    Alright, thanks for the help!

  4. #4
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    Hey again. I just compiled that piece of code, and when I used it, it complained that 2 operators have similar overloads, or something like that. I know that theyre similar, but since one has higher precedence, shouldn't it know which one to use?

    Thanks!

  5. #5
    & the hat of GPL slaying Thantos's Avatar
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    overloading has nothing to do with operator precedence. Can you show the actual code because there is no overloading in what you showed.

  6. #6
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    My code up there has overloading in it. I overloaded the subscript and typecast operators. The compiler is compaining though...

  7. #7
    & the hat of GPL slaying Thantos's Avatar
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    *sigh* You don't have a complete program, where is the main? Also its not overloading in that case. Overloading is when you have multiple functions with the same name but different parameters.

    Without the operator[] or operator Type* functions you wouldn't be able to use those two at all. So post the actual code you are trying to compile.

    Edit: And include the exact error message.

  8. #8
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    Array syntax- array[i], is equivalent to *(array + i). It appears the compiler cannot figure out which of those versions to use.

    Did you mean to use operator *() instead of operator Type*()?

  9. #9
    Skunkmeister Stoned_Coder's Avatar
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    You can ensure that operator [] gets called by doing this...

    MyArray.operator [](1) = 6;

    but it would be a better idea to do away with the conversion operator altogether. if you must then make an explicit function called to_array() or similar then where you would normally depend upon an implicit conversion you instead must state explicitly by calling to_array(). This has the effect of making your code safer and more readable. a win-win situation.
    Free the weed!! Class B to class C is not good enough!!
    And the FAQ is here :- http://faq.cprogramming.com/cgi-bin/smartfaq.cgi

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