Help with problem in my C++ book

[bmwboi]

Alright, so I just went through a chapter of my book, and started to do the practice problems, however, there are two that I just can't seem to figure out. Here are the questions:


5.

Rewrite the Stonewt class (Listings 11.16 and 11.17) so that it has a state member that governs whether the object is interpreted in stone form, integer pounds form, or floating-point pounds form. Overload the << operator to replace the show_stn() and show_lbs() methods. Overload the addition, subtraction, and multiplication operators so that one can add, subtract, and multiply Stonewt values. Test your class with a short program that uses all the class methods and friends.



6.

Rewrite the Stonewt class (Listings 11.16 and 11.17) so that it overloads all six relational operators. The operators should compare the pounds members and return a type bool value. Write a program that declares an array of six Stonewt objects and initializes the first three objects in the array declaration. Then it should use a loop to read in values used to set the remaining three array elements. Then it should report the smallest element, the largest element, and how many elements are greater or equal to 11 stone. (The simplest approach is to create a Stonewt object initialized to 11 stone and to compare the other objects with that object.)

Listing 11.16

// stonewt.h -- definition for the Stonewt class
#ifndef STONEWT_H_
#define STONEWT_H_
class Stonewt
{
private:
    enum {Lbs_per_stn = 14};      // pounds per stone
    int stone;                    // whole stones
    double pds_left;              // fractional pounds
    double pounds;                // entire weight in pounds
public:
    Stonewt(double lbs);          // constructor for double pounds
    Stonewt(int stn, double lbs); // constructor for stone, lbs
    Stonewt();                    // default constructor
    ~Stonewt();
    void show_lbs() const;        // show weight in pounds format
    void show_stn() const;        // show weight in stone format
};
#endif 

Listing 11.17

// stonewt.cpp -- Stonewt methods
#include <iostream>
using std::cout;
#include "stonewt.h"

// construct Stonewt object from double value
Stonewt::Stonewt(double lbs)
{
    stone = int (lbs) / Lbs_per_stn;    // integer division
    pds_left = int (lbs) % Lbs_per_stn + lbs - int(lbs);
    pounds = lbs;
}

// construct Stonewt object from stone, double values
Stonewt::Stonewt(int stn, double lbs)
{
    stone = stn;
    pds_left = lbs;
    pounds =  stn * Lbs_per_stn +lbs;
}

Stonewt::Stonewt()          // default constructor, wt = 0
{
    stone = pounds = pds_left = 0;
}

Stonewt::~Stonewt()         // destructor
{
}

// show weight in stones
void Stonewt::show_stn() const
{
    cout << stone << " stone, " << pds_left << " pounds\n";
}

// show weight in pounds
void Stonewt::show_lbs() const
{
    cout << pounds << " pounds\n";
}

Thank you in advanced!

[Zhuge]

So...what is your question?

[bmwboi]

I thought it was obvious... my question is how would I solve those two questions, with the 2 codes given.

[Zhuge]

What part of the questions are you having trouble with?

[bmwboi]

I just don't know how to go about solving these... Probably because I don't understand operator overloading so well... But if I could get help from start to finish, that would be cool

[codekiddy]

Probably because I don't understand operator overloading

It looks you didn't read the book from begining :)
return to the chapter "opeartor overloding"

Here is an "hipotetic" example to replace show_lbs() as requested in question 5

ostream& operator<<(int what /* implement this */) const
{
      static ostream os;
      os << this->pounds;
      return os;
}

edit:
I hope I got that wright? (check your self)