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Help with output operator

Posted on 2003-10-29
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Last Modified: 2010-04-02
I am trying to take the following header and implementation files and changed them so that an output operator, <<, can be used. The code Point P(14.3, 4.2);
                       cout<<P;
should produce an utput of (14.3, 4.2). What modifications would be necessary to make this happen?
here is my code so far:

header:
#ifndef POINT_H
#define POINT_H
#include <iostream>
#include <conio>

using namespace std;

class Point
{
public:
Point (); //constructor
Point (double, double); //constructor

double GetX () const;
double GetY () const;

private:
double x;
double y;
};
#endif

and the implementation file:
#pragma hdrstop
#include "point.h"
Point::Point ()
{
     x=0;
     y=0;
}

Point::Point ( double InputX, double InputY)
{
x=InputX;
y=InputY;
}

double Point::GetX () const
{
      return x;
}

double Point::GetY () const
{
     return y;
}

please help me out on this
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Question by:jba6511
  • 3
6 Comments
 
LVL 86

Accepted Solution

by:
jkr earned 250 total points
ID: 9645613
You'll need a global 'operator<<()', as you cannot add that functionality to 'cout', e.g.

ostream& operator << ( ostream& r, Point& l) {

  r << "(" << l.GetX() << ", " << l.GetY() << ")";

  return r;
}

As the above only uses public members of 'Point', you won't even need to make it a 'friend'.
0
 

Author Comment

by:jba6511
ID: 9645942
what would need to be done if i was to make it a friend then?
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LVL 86

Expert Comment

by:jkr
ID: 9645962
>>what would need to be done if i was to make it a friend then?

You'd use

class Point
{
public:

friend ostream& operator << ( ostream& r, Point& l);

//...
};

in your class definition - but, this is not even necessary...

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LVL 86

Expert Comment

by:jkr
ID: 9671377
Do you have any further problems with this one?
0
 
LVL 9

Expert Comment

by:tinchos
ID: 10546303
No comment has been added lately, so it's time to clean up this question.
I will leave the following recommendation for this question in the Cleanup topic area:

Accept: jkr {http:#9645613}

Please leave any comments here within the next four days.
PLEASE DO NOT ACCEPT THIS COMMENT AS AN ANSWER!

Tinchos
EE Cleanup Volunteer
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