Question

Consider this declaration of the class Fraction:
class Fraction {
private:
int numerator, denominator;
public:
Fraction operator+(const Fraction & frac2);
Fraction & setNumerator(int numer);
Fraction & setDenominator(int denom);
};
a. Why is there only one parameter, frac2, used with operator+, even though addition
has two operands?
b. Write the operator:
Fraction Fraction::operator+ (Fraction frac2){
}
c. Write setNumerator() and setDenominator() as cascading functions:
Fraction & Fraction::setNumerator(int numer) {
}
Fraction & Fraction::setDenominator(int denom) {
}
d. Assign the fractions frac1 to 3/5, and frac2 to 7/8, using cascading functions:
Fraction frac1; frac1______________________________;
Fraction * frac2 = new Fraction; frac2______________________________;
e. Write an operator Fraction::operator!() which performs inversion.
For example, if x is 3/5 then !x is 5/3.

Answer 1

a. Why is there only one parameter, frac2, used with operator+, even though addition
has two operands?

This is because the operation + is applied on the object which calls it using this pointer.
b. Write the operator:
Fraction Fraction::operator+ (Fraction frac2){
}

Fraction Fraction::operator+(const Fraction & frac2)
{
this->numerator=this->numerator*frac2.denominator+frac2.numerator*this->denominator;
this->denominator=this->denominator*frac2.denominator;
return *this;
}
c. Write setNumerator() and setDenominator() as cascading functions:
Fraction & Fraction::setNumerator(int numer) {
}
Fraction & Fraction::setDenominator(int denom) {
}

Fraction & Fraction::setNumerator(int numer)
{
       numerator = numer;
   return *this;
}
Fraction & Fraction::setDenominator(int denom)
{
   denominator = denom;
   return *this;
}
d. Assign the fractions frac1 to 3/5, and frac2 to 7/8, using cascading functions:
Fraction frac1; frac1______________________________;
Fraction * frac2 = new Fraction; frac2______________________________;

Fraction frac1;
   frac1.setNumerator(3);
   frac1.setDenominator(5);

   Fraction * frac2 = new Fraction;
   frac2->setNumerator(7);
   frac2->setDenominator(8);

e. Write an operator Fraction::operator!() which performs inversion.
For example, if x is 3/5 then !x is 5/3.

Fraction Fraction::operator!()
{
   int temp = this->numerator;
   this->numerator = this->denominator;
   this->denominator = temp;
   return *this;
}

Full Code:

#include <iostream>
using namespace std;

class Fraction {
private:
int numerator, denominator;
public:
Fraction operator+(const Fraction & frac2);
Fraction& setNumerator(int numer);
Fraction& setDenominator(int denom);
Fraction operator!();
void display();
};

Fraction Fraction::operator+(const Fraction & frac2)
{

this->numerator=this->numerator*frac2.denominator+frac2.numerator*this->denominator;
this->denominator=this->denominator*frac2.denominator;
return *this;
}
Fraction & Fraction::setNumerator(int numer)
{
  
   numerator = numer;
   return *this;
}
Fraction & Fraction::setDenominator(int denom)
{
   denominator = denom;
   return *this;
}
Fraction Fraction::operator!()
{
   int temp = this->numerator;
   this->numerator = this->denominator;
   this->denominator = temp;
   return *this;
}
void Fraction::display()
{
   cout<<"\n"<<numerator<<"/"<<denominator;
}

int main() {
  
   Fraction frac1;
   frac1.setNumerator(3);
   frac1.setDenominator(5);
  
   Fraction frac;
   frac.setNumerator(4);
   frac.setDenominator(7);
  
  
   Fraction * frac2 = new Fraction;
   frac2->setNumerator(7);
   frac2->setDenominator(8);
  
   frac1+frac;
   frac1.display();
  
   !frac1;
  
   frac1.display();
   return 0;
}

Output:

41/35
35/41

Do ask if any doubt. Please upvote.