Question

I am writing a program that will work with two other files to add or subtract fractions for as many fractions that user inputs. I need to overload the + and - and << and >> opperators for the assignment. The two files posted cannot be modified. Can someone correct the Fraction.ccp and Frction.h file that I am working on? I'm really close.

//
// useFraction.cpp
//
// DO NOT MODIFY THIS FILE
//

#include "Fraction.h"
#include<iostream>
using namespace std;

void print_fraction(const Fraction& f)
{
  cout << "print_fraction: " << f.getNum() << "/" << f.getDen() << endl;
}

int main()
{
  Fraction x(2,3);
  Fraction y(6,-2);

  cout << x << endl;
  cout << y << endl;

  cin >> y;
  cout << y << endl;
  print_fraction(y);
  Fraction z = x + y;
  cout << x << " + " << y << " = " << z << endl;
}

//
// calculator.cpp
//
// DO NOT MODIFY THIS FILE
//

#include "Fraction.h"
#include<iostream>
#include<stdexcept>
using namespace std;

int main()
{
  Fraction x,y;
  char op;
  try
  {
    cin >> x;
    cin >> op;
    while ( cin && ( op == '+' || op == '-' ) )
    {
      cin >> y;
      if ( op == '+' )
        x = x + y;
      else
        x = x - y;
      cin >> op;
    }
    cout << x << endl;
  }
  catch ( invalid_argument& e )
  {
    cout << "Error: " << e.what() << endl;
  }
}

//MYFILES

//fraction.cpp
Fraction::Fraction()
{
num = 0;
dem = 1;
}
Fraction::Fraction(int a, int b){
num = a;
dem = b;
}
int Fraction::getNum(){
return num;
}
int Fraction::getDen(){
return den;
}
void Fraction::setNum(int a)
{
num = a;
}
void Fraction::setDen(int b)
{
den = b;
}
Fraction Fraction ::operator+( const Fraction & rightFraction )
{
Fraction temp;
temp.num = ( num * rightFraction.den ) + ( den * rightFraction.num );
temp.den = den * rightFraction.den;
return temp;
} // end function operator+
Fraction Fraction ::operator-( const Fraction & rightFraction )
{
Fraction temp;
temp.num = ( num * rightFraction.den ) - ( den * rightFraction.num );
temp.den = den * rightFraction.den;
return temp;
} // end function operator-
ostream& operator<<(ostream& os, const Fraction& f)
{
os << f.getNum() << "/" << f.getDen(); // output in fraction format
return os;
}
istream& operator>>(istream& is, Fraction& f)
{
int t, b;
do
{
// Read the numerator first
is >> t;
char c;
is >> c;
if (c == '/') // If there is a slash, then read the next number
is >> b;
else //otherwise just "unget()" it and set to b=1
{
is.unget();
b = 1;
}
if (b==0) // if b came out to 0, fraction is not possible, so we loop back to ask user input again
throw "Error: divide by zero ";
} while(b==0);
f = Fraction(t, b); // set the fraction
return is;
}
//Header file

#indef

#def

class Fraction{
public:
Fraction();
Fraction(int, int);
getNum();
getDen();
setNum(int);
setDen(int);
friend operator-( const Fraction & rightFraction );
friend operator+( const Fraction & rightFraction );
friend ostream& operator<<(ostream& os, const Fraction& f);
friend istream& operator>>(istream& is, Fraction& f);

private:
int num;
int den;
};

Answer 1

calculator.cpp

//
// calculator.cpp
//
#include "Fraction.h"
#include<iostream>
#include<stdexcept>
using namespace std;

int main()
{
Fraction x,y;
char op;
try
{
    cin >> x;
    cin >> op;
    while ( cin && ( op == '+' || op == '-' ) )
    {
      cin >> y;
      if ( op == '+' )
        x = x + y;
      else
        x = x - y;
      cin >> op;
    }
    cout << x << endl;
}
catch ( invalid_argument& e )
{
    cout << "Error: " << e.what() << endl;
}
}

Fraction.h

#ifndef Fraction_h
#define Fraction_h
#include <iostream>
using namespace std;
class Fraction
{
public:
//Functions
Fraction();
Fraction(int,int);
   int getNum() const;
   int getDem() const;
   void setNum(int num);
   void setDem(int den);
   void reduce();
   void signs();
   friend   ostream& operator<<(ostream &out,const Fraction &);
   friend   istream& operator>>(istream &,Fraction &);
   Fraction operator+(const Fraction );
   Fraction operator-(const Fraction );
   Fraction& operator=(const Fraction );
private:
int nemer;
int denom;
};
#endif

Fraction.cpp

#include "Fraction.h"
#include <stdexcept>
#include <iostream>
#include <cstdlib>
using namespace std;
Fraction::Fraction()
{
   setNum(0);
   setDem(0);
}
Fraction::Fraction(int nem, int dem)
{
   if (dem == 0)
   {
       throw invalid_argument("division by zero");
   }
   else
   {
       setNum(nem);
       setDem(dem);
       reduce();
   }
  
}
void Fraction::setNum(int num)
{
   nemer = num;
}
void Fraction::setDem(int den)
{
   denom = den;
}
int Fraction::getNum() const
{
   return nemer;
}
int Fraction::getDem() const
{
  
   return denom;
}
void Fraction::reduce()
{
   signs();
   int Sign = 1;
   int nem = getNum();
   int den = getDem();
   if (nem < 0)
   {
       nem *= -1;
       Sign = -1;
   }
   for (int i = (nem * den); i > 1; i--)
   {
       if ((nem % i == 0) && (den % i == 0))
       {
           nem /= i;
           den /= i;
       }
   }
   nem *= Sign;
   setNum(nem);
   setDem(den);
}
void Fraction::signs()
{
   int nem = getNum();
   int den = getDem();
   if (den < 0)
   {
       nem *= -1;
       den *= -1;
   }
   setNum(nem);
   setDem(den);
}
Fraction &Fraction::operator=(const Fraction frac)
{
   int num = frac.getNum();
   int den = frac.getDem();
   (*this).setNum(num);
   (*this).setDem(den);
   return *this;
}
istream &operator>>(istream &in, Fraction &frac)
{
   char Dum;
   int num;
   int den;
   in >> num;
   in >> Dum;
   in >> den;
   if (den == 0)
   {
       throw invalid_argument("Error: division by zero");
       exit(0);
   }
   frac.setNum(num);
   frac.setDem(den);
   frac.reduce();
   return in;
}
ostream &operator<<(ostream& out, const Fraction& frac)
{
;
   if (frac.getDem() == 1)
       out << frac.getNum();
   else
   {
       out << frac.getNum() << '/' << frac.getDem();
      
   }
   return out;
}
Fraction Fraction::operator+(const Fraction frac)
{
   int Nsum = ((*this).getNum() * frac.getDem()) + (getNum() * (*this).getDem());
   int Dsum = ((*this).getDem() * frac.getDem());
   Fraction frac2(Nsum, Dsum);
   frac2.reduce();
   return frac2;
}
Fraction Fraction::operator-(const Fraction frac)
{
   int Nsum= ((*this).getNum() * frac.getDem()) - (getNum() * (*this).getDem());
   int Dsum = ((*this).getDem() * frac.getDem());
   Fraction frac2(Nsum, Dsum );
   frac2.reduce();
   return frac2;
}

useFraction.cpp

//
// useFraction.cpp
//

#include "Fraction.h"
#include<iostream>
using namespace std;

int main()
{
Fraction x(2,3);
Fraction y(6,-2);

cout << x << endl;
cout << y << endl;

cin >> y;
cout << y << endl;
Fraction z = x + y;
cout << x << " + " << y << " = " << z << endl;
}