Newbie : Problem with a friend function

From: mark page (mpage1_at_socal.rr.com)
Date: 10/12/03 

Date: Sun, 12 Oct 2003 19:44:17 GMT

Hi to all

I am a newcomer to C++ and I am working my way through the book "C++ Primer
Third Edition".

I have a problem with one example and I am given the error message

: error C2248: 'hours' : cannot access private member declared in class
'Time'
: error C2248: 'minutes' : cannot access private member declared in class
'Time'

The problem relates to a Class Time and within it I have defined a friend
function to access the private data members.

When I program the function inline within the class definition everthing
works, However, when the function definition is defined outside the class I
have the above problem. I am using the Visual C++ compiler version 6.

here is the code and I have highlighted the offending function with
comments.
// mytime.h -- class definition for time class
// demonstrates an overloaded operator for the Addition member
// includes friend functions

#ifndef _MYTIME_H_
#define _MYTIME_H_
#include <iostream>
using namespace std;

class Time
{
private:
 int hours;
 int minutes;
public:
 Time();
 Time(int h, int m = 0);
 void AddMin(int m);
 void AddHr(int h);
 void Reset(int h = 0, int m = 0);
 Time operator+(const Time & t) const; // overloading the + operator to add
objects
 Time operator-(const Time & t) const; // overloading the - operator to
subtract objects
 Time operator*(double n) const; // overloading the * operator to
multiply objects by a factor
 friend Time operator*(double m, const Time & t)
  { return t * m;} // inline definiton
 // ************ problem function *********************
 friend ostream & operator<<(ostream & os, const Time & t);

};
#endif

// mytime.cpp -- Time class method definitions

#include "mytime.h"

Time::Time()
{
 hours = minutes = 0;
}

Time::Time(int h, int m)
{
 hours = h;
 minutes = m;
}

void Time::AddMin(int m)
{
 minutes += m;
 hours += minutes / 60;
 minutes %= 60;
}

void Time::AddHr(int h)
{
 hours += h;
}

void Time::Reset(int h, int m)
{
 hours = h;
 minutes = m;
}

Time Time::operator +(const Time & t) const // overloading the + operator
to add objects
{
 Time sum;
 sum.minutes = minutes + t.minutes;
 sum. hours = hours + t.hours + sum.minutes / 60;
 sum.minutes %= 60;
 return sum;
}

Time Time::operator-(const Time & t) const // overloading the - operator to
subtract objects
{
 Time diff;
 int tot1, tot2;
 tot1 = t.minutes + 60 * t.hours;
 tot2 = minutes + 60 * hours;
 diff.minutes = (tot2 - tot1) % 60;
 diff.hours = (tot2 - tot1) / 60;
 return diff;
}

Time Time::operator*(double mult) const // overloading the * operator to
multiply objects by a factor
{
 Time result;
 long totalminutes = hours * mult * 60 + minutes * mult;
 result.hours = totalminutes / 60;
 result.minutes = totalminutes % 60;
 return result;
}

// ***** problem function *********************************

ostream & operator<<(ostream & os, const Time & t)
{
 os << t.hours << " hours, " << t.minutes << " minutes";
 return os;
}

please help

mark

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