Question

Define a class for rational numbers. A rational number is a "ratio-nal" number, composed of two integers with division indicated. 

Requirement:
- two member variables: (int) numerator and (int) denominator. 
- two constructors: one that takes in both numerator and denominator to construct a rational number, and one that takes in only numerator and initialize the denominator as 1. 
- accessor/modifier
- member functions: add(), sub(), mul(), div(), and less(). Usage: to add rational num b and rational num a, one could call a.add(b); to compare rational num a and rational num b, one could call a.less(b). add(), sub(), mul() and div() should return a rational number.  
- member functon: factor(). This function should be a private function that should be called each time numerator/denominator is set/modified. The purpose of this function is to take the greatest common factor out of numerator/denominator. For example, rational number 2/4 should be stored as 1/2, rational number 3/9 should be stored as 1/3. 
- fully test all public functions inside main(). 

in c++

Answer 1

#include <iostream>
#include <string>
#include <cmath>
using namespace std;

class RationalNumber
{
public:
  
RationalNumber(int n);

// Initializes the rational number to wholeNumber/1
RationalNumber(int m, int n);

bool less(RationalNumber r2);

//Declaring functions
void add(RationalNumber rn);
void sub(RationalNumber rn);
void mul(RationalNumber rn);
void div(RationalNumber rn);
int getNumerator();
int getDenominator();
void setNumerator(int numer);
void setDenominator(int denom);

private:
// Declaring variables
int numerator; // the numerator of the number
int denominator; // the denominator of the number
int factor(int a, int b);
};

RationalNumber::RationalNumber(int n)
{
this->numerator=n;
this->denominator=1;
}

// Initializes the rational number to wholeNumber/1
RationalNumber::RationalNumber(int m, int n)
{
if(denominator<0)
{
this->numerator=-(m);
this->denominator=-(n);
}
else
{
this->numerator=(m);
this->denominator=(n);
}

}

bool RationalNumber::less(RationalNumber r2)
{
int a = numerator;
int b = denominator;
int c = r2.numerator;
int d = r2.denominator;
double n1 = a * d;
double d1 = b * d;
double n2 = c * b;
double d2 = d * b;
if ((n1 / d1) < (n2 / d2))
return true;
else
return false;

}
int RationalNumber::getNumerator()
{
return numerator;
}
int RationalNumber::getDenominator()
{
return denominator;
}
void RationalNumber::setNumerator(int numer)
{
this->numerator=numer;
}
void RationalNumber::setDenominator(int denom)
{
this->denominator=denom;
}

int RationalNumber::factor(int a, int b)
{
// % is modulus which is the remainder of a division
// base case
if ((a % b) == 0)
{
return b;
}
// recursive case
else
{
return factor(b, a % b);
}

}
//This method will add two rational numbers
void RationalNumber::add(RationalNumber rn)
{
int a,b,c,d;
a=getNumerator();
b=getDenominator();
c=rn.getNumerator();
d=rn.getDenominator();
int sumnumer=(a*d + b*c);
int sumdenom=(b*d);
  
int g=factor(sumnumer,sumdenom);
if(sumdenom!=1)
cout<<sumnumer/g<<"/"<<sumdenom/g;
else
cout<<sumnumer/g;

}
//This method will subtract two rational numbers
void RationalNumber::sub(RationalNumber rn)
{
int a,b,c,d;
a=getNumerator();
b=getDenominator();
c=rn.getNumerator();
d=rn.getDenominator();
int subnumer=(a*d - b*c);
int subdenom=(b*d);
int g=factor(subnumer,subdenom);
if(subdenom!=1)
cout<<subnumer/g<<"/"<<subdenom/g;
else
cout<<subnumer/g;
}
//This method will multiply two rational numbers
void RationalNumber::mul(RationalNumber rn)
{
int a,b,c,d;
a=getNumerator();
b=getDenominator();
c=rn.getNumerator();
d=rn.getDenominator();
int mulnumer=(a*c);
int muldenom=(b*d);
int g=factor(mulnumer,muldenom);
if(muldenom!=1)
cout<<mulnumer/g<<"/"<<muldenom/g;
else
cout<<mulnumer/g;
}
//This method will divide two rational numbers
void RationalNumber::div(RationalNumber rn)
{
int a,b,c,d;
a=getNumerator();
b=getDenominator();
c=rn.getNumerator();
d=rn.getDenominator();   
int divnumer=(a*d);
int divdenom=(c*b);
int g=factor(divnumer,divdenom);
if(divdenom!=1)
cout<<divnumer/g<<"/"<<divdenom/g;
else
cout<<divnumer/g;
}

int main()
{
//Creating the objects to RationalNumber class
RationalNumber rn1(1,6);
RationalNumber rn2(2);

//Getting the number entered by the user
cout<<"First Number:";
cout<<rn1.getNumerator()<<"/"<<rn1.getDenominator()<<endl;
cout<<"\nSecond Number:";
cout<<rn2.getNumerator()<<"/"<<rn2.getDenominator()<<endl;

/* calling the function and displaying
* the result after adding two rational num bers
*/
cout<<"\nAddition :";
rn1.add(rn2);
/* calling the function and displaying
* the result after subtracting two rational num bers
*/
cout<<"\nSubtraction :";
rn1.sub(rn2);
/* calling the function and displaying
* the result after multiplying two rational num bers
*/
cout<<"\nMultiplication :";
rn1.mul(rn2);
/* calling the function and displaying
* the result after dividing two rational num bers
*/
cout<<"\nDivision :";
rn1.div(rn2);

bool b=rn1.less(rn2);
if(b)
{
cout<<"\nRationalNumber#1 is Less than RationalNumber#2"<<endl;
}
else
{
cout<<"\nRationalNumber#1 is not Less than RationalNumber#2"<<endl;
}

return 0;
}

output: