//       CS 212 Assignment 4
//
//       Filename:      hw4.cpp
//
//       Author:        Nathan Lutz
//
//       Instructor:    Dr. Wang
//       Due:           Feb 27, 2008
//       Compile:       g++ hw4.cpp -o a.out
//       Run:           ./a.out
//       Purpose:	write a program to read two fractions and an operator +, -, *, or /, perform the operation, output the result. 

#include <iostream>

using namespace std;

class Fraction
{
	int num, den;
public:
	Fraction()						// Default 0/1
	{
		num=0;
		den=1;
	}

	Fraction(int n, int d)
	{
		num=n; 
		den=d;
	}

	void Set(int n, int d)
	{
		num=n;
		den=d;
	}

	void Print() const 
	{
		cout<<num<<"/"<<den;
	}

	Fraction Add (Fraction x)
	{
		Fraction answer;
		int n,d;
		d = Fraction :: den * x.den;
		n = num * x.den + den*x.num;
		answer.Set(n,d);
		return answer;
	}

	Fraction Sub (Fraction x)
	{
		Fraction answer;
                int n,d;
                d = Fraction :: den * x.den;
                n = num * x.den -  den*x.num;
                answer.Set(n,d);
                return answer;
	}

	Fraction Mult (Fraction x)
	{
		Fraction answer;
		int n,d;
		n = num*x.num;
		d = den*x.den;
		answer.Set(n,d);
                return answer;
	}
	Fraction Div (Fraction x)	
	{
		Fraction answer;
                int n,d;
                n = num/x.num;
                d = den/x.den;
                answer.Set(n,d);
                return answer;
	}
};

int main()
{
	int nu,de;
	char dummy,op;
	Fraction x,y,z;
	cout<<"Input x: (-1/1 to quit) "<<endl;
	cin>>nu>>dummy>>de;
	while (nu!=-1 && de!=1)
	{
		x.Set(nu,de);
		cout<<"Input y: "<<endl;
		cin>>nu>>dummy>>de;
		y.Set(nu,de);
		cout<<"Input the operation: "<<endl;
		cin>>op;
		if (op=='+')
                {
                        z=x.Add(y);
                        x.Print();
			cout<<" + ";
			y.Print();
			cout<<" = ";
			z.Print();
                }
	        else if (op=='-')
                {
                        z=x.Sub(y);
                        x.Print();
                        cout<<" - ";
                        y.Print();
                        cout<<" = ";                    
                        z.Print();
                }
	        else if (op=='*')
                {
                        z=x.Mult(y);
                        x.Print();
                        cout<<" * ";
                        y.Print();
                        cout<<" = ";                    
                        z.Print();
                }
		else if (op=='/')
                {
                        z=x.Div(y);
                        x.Print();
                        cout<<" / ";
                        y.Print();
                        cout<<" = ";                    
                        z.Print();
                }
		else
		cout<<"This is not a valid operation."<<endl;	
		cout<<"\nInput x: (-1/1 to quit)"<<endl;
		cin>>nu>>dummy>>de;
	}
	cout<<"\n\nThank you."<<endl;
	return 0;	
}

******************************************************************************************************************
Output:

[ndlutz@zeus CS212]$ ./a.out
Input x: (-1/1 to quit) 
1/3
Input y: 
1/2
Input the operation: 
*
1/3 * 1/2 = 1/6
Input x: (-1/1 to quit)
1/2
Input y: 
1/2
Input the operation: 
+
1/2 + 1/2 = 4/4
Input x: (-1/1 to quit)
-1/1


Thank you