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Constructor - able to take 0 or more arguments

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Join Date: Feb 2005

Posts: 154

Reputation: tones1986 is an unknown quantity at this point

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tones1986

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Junior Poster

Constructor - able to take 0 or more arguments

Mar 17th, 2008

Hey folks. I am confused as to how i can make a constructor take zero - or lets say 3 arguments. If i do this in my main.cpp:

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   const Vector  v1;
   const Vector v2(1.0, 2.0, 3.0);
   const Vector  v1;
   const Vector v2(1.0, 2.0, 3.0);

And this in my vector.cpp file:

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Vector::Vector(double new_x, double new_y, double new_z)
{
  x = 0;
  y = 0;
  z = 0;
}
Vector::Vector(double new_x, double new_y, double new_z)
{
  x = 0;
  y = 0;
  z = 0;
}

And then this in my vector.h file:

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 ...
...
public:
        //Vector();
        Vector(double, double, double);
 
   };
 ...
...
public:
        //Vector();
        Vector(double, double, double);
   
   };

I get an error saying this:

23 C:\Users\Tony\Documents\csci 241\Assign4\assign4.cpp no matching function for call to `Vector::Vector()'

THis makes sense as there is no constructor like this within my .h or .cpp file - so it doesnt know what to do. But i MUST have only one constructor, is this possible?

Hope you guys can help out again

Thanks in advance

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Join Date: Feb 2008

Posts: 15

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dophine

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Newbie Poster

Re: Constructor - able to take 0 or more arguments

Mar 17th, 2008

as you provide a constructor, the compiler does not generate a default constructor which takes no parameter for you.

so if you want a constructor to take zero parameter, then you must define it.
or you can try this to provide default value

Vector::Vector(double new_x=2.0, double new_y=2.0, double new_z=2.0)

Last edited by dophine; Mar 17th, 2008 at 1:12 pm.