operator overloading

This is a discussion on operator overloading within the C++ Programming forums, part of the General Programming Boards category; i have another assignment (the last thank goodness) but here it is... i have to write the definitions for the ...

  1. #1
    cereal killer dP munky's Avatar
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    operator overloading

    i have another assignment (the last thank goodness) but here it is...

    i have to write the definitions for the functions in a class....these happen to deal w/funciton overloading, i had a similar assignment earlier....am i doing this right? //the first one imparticular
    Code:
    		// prefix ++ operator
    		Point& operator++(pt)
    		{
    			x_ = pt.x_++;
    			y_ = pt.y_++;
    			z_ = pt.z_++;
    		}
    
    		const Point operator++(int);		// postfix ++ operator
    
    		Point& operator-(); 				// prefix -- operator
    		const Point operator-(int);		// postfix -- operator
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  2. #2
    Skunkmeister Stoned_Coder's Avatar
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    nope. remember the int passed is a dummy arg to differentiate post and pre.
    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

  3. #3
    cereal killer dP munky's Avatar
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    excuse me for being retarded but....huh?
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  4. #4
    ¡Amo fútbol!
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    The integer passed as an argument has no use to you. It just tells the compiler whether the operator is postfix or prefix.

  5. #5
    cereal killer dP munky's Avatar
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    so then how do i make it usefull to me? remove it?
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  6. #6
    Skunkmeister Stoned_Coder's Avatar
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    ok here we go again post and pre for dummies....
    Code:
    class plonker
    {
       private: 
         int wally;
       public:
         plonker() : wally(0){}
         plonker(int w) : wally(w){}
         plonker& operator ++() 
         {
             ++wally;
             return *this;
         }
         const plonker operator ++(int)
         {
            int temp = wally;
            ++(*this); // implement post in terms of pre for symettry
            return temp;
         }
    };
    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

  7. #7
    ¡Amo fútbol!
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    Check this out.

  8. #8
    cereal killer dP munky's Avatar
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    getting warmer???

    Code:
    		// prefix ++ operator
    		Point& operator++()
    		{
    			++x_;
    			++y_;
    			++z_;
    			return *this;
    		}
    
    		// postfix ++ operator
    		const Point operator++(int)
    		{
    			int temp = *this;
    			++(*this);
    
    			return temp;
    
    		}
    Last edited by dP munky; 04-17-2003 at 10:17 PM.
    guns dont kill people, abortion clinics kill people.

  9. #9
    Skunkmeister Stoned_Coder's Avatar
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    1) fine
    2)crap. try again
    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

  10. #10
    Skunkmeister Stoned_Coder's Avatar
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    look im off to bed so one last piece of advice.......

    Use the constructor......
    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

  11. #11
    Crazy Fool Perspective's Avatar
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    >> int temp = *this;


    think about what 'this' is and what your assigning it to. 'this' is not an int.

  12. #12
    cereal killer dP munky's Avatar
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    this should be my 3 ints...right? this is a pointer to x_ y_ and z_ or am i misunderstanding that?

    im looking at this web site and it says to just do

    ++(*this);

    am i doing to mucH?
    Last edited by dP munky; 04-17-2003 at 10:50 PM.
    guns dont kill people, abortion clinics kill people.

  13. #13
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    The problem is here:

    int temp = *this;

    this is a pointer, and like all pointers it points to one thing, not three things. What does this point to? this is a pointer to the object you are calling the function on, so *this is the object. The object's type is the class name not int.

    "the int passed is a dummy arg to differentiate post and pre."

    Try defining post and prefix ++ operators with out using the dummy int:

    operator++()

    operator++()

    Those are exactly the same, so the compiler can't tell the difference. You need int as a dummy argument to differentiate the two:

    operator++()
    operator++(int)

    Since there is no requirement that you have to use an argument that's passed to your function, ignore it in your function definition.
    Last edited by 7stud; 04-18-2003 at 01:45 AM.

  14. #14
    Skunkmeister Stoned_Coder's Avatar
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    well did you get it right?

    Code:
    const Point operator++(int)
    {
       Point temp(*this); // call copy con to make copy of current object
       ++(*this);
       return temp;
    }
    Its that simple.
    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

  15. #15
    cereal killer dP munky's Avatar
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    i had

    Point temp = *this;

    but i went to bed shortly after that, i had another assignment due at midnight i was rushin to get done
    guns dont kill people, abortion clinics kill people.

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