package fractions;
import java.util.*;
public class Fraction
{
 private Scanner scan = new Scanner(System.in);
 private int num=1;
 private int denom=1;

 public Fraction()
 {
 }

 public Fraction(int n, int d)
 {
	this.num = n;
	this.denom = d;
 }

 public void setFraction(int n, int d)
 {
	this.num = n;
	this.denom = d;
 }

 public Fraction add(Fraction op)
 {
 // Algebra HINT: a/b + c/d = (a*d + b*c)/(b*d)
	op.num = (this.num * op.denom + this.denom * op.num);
	op.denom = (this.denom * op.denom);
	op.reduce();
	return op;
 }

 public Fraction subtract(Fraction op)
 {
 // Algebra HINT: a/b - c/d = (a*d - b*c)/(b*d)
	op.num = (this.num * op.denom - this.denom * op.num);
	op.denom = (this.denom * op.denom);
	op.reduce();
	return op;
 }

 public Fraction multiply(Fraction op)
 {
 // Algebra HINT: a/b * c/d = (a*c)/ (b*d)
	op.num = (this.num * op.num);
	op.denom = (this.denom * op.denom);
	op.reduce();
	return op;
 }

 public Fraction divide(Fraction op)
 {
 // Algebra HINT: a/b / c/d = (a*d)/ (b*c)
	this.num = (this.num * op.denom);
	this.denom = (this.denom * op.num);
	this.reduce();
	return this;
 }

 private void reduce()
 {
	 int smaller;
	 if(this.num > this.denom)
	 {
		 smaller = denom;
	 }
	 else
	 {
		 smaller = num;
	 }
	 for(int divisor = 2; divisor < smaller; divisor++)
	 {
		  while ((num%divisor == 0)&&(denom%divisor == 0))
		  {
			  num /= divisor;
			  denom /= divisor;
		  }
	 }
 }

 public boolean equals(Fraction f)
 {
	 f.reduce();
	 this.reduce();
	 if((this.num == f.num)&&(this.denom == f.denom))
	 {
		 return true;
	 }
	 else return false;
 }

 public String toString()
 {
	 this.reduce();
	 return (this.num + "/" + this.denom);
 }

 public void readin(String label)
 {
 while (true) // Keep trying if bad input is received
 {
 System.out.print(label);
 String temp = scan.next();
 temp = temp.trim(); // get rid of white space at the beginning and end
 int index = temp.indexOf('/');
 if (index >= 0)
 {
 String numStr = temp.substring(0, index);
 String denomStr = temp.substring(index+1);
 int n = Integer.parseInt(numStr);
 int d = Integer.parseInt(denomStr);
 setFraction(n,d);
 return;
 }
 else
 System.out.println("Input Fraction missing / ");
 }//Keep trying until you get it right
 }

 public static void main(String[] args)
 {
 Fraction f1= new Fraction();
 Fraction f2= new Fraction();
 Fraction f3= null;
 Scanner scan = new Scanner(System.in);

 while(true)
 {
 System.out.println(); // Add a blank line
 System.out.print("Enter operation: + - * / q (q ==> quit) : ");
 String input = scan.next();
 if (input.charAt(0) == 'q')
 break; // All done

 f1.readin("Enter Fraction 1: ");
 f2.readin("Enter Fraction 2: ");
 System.out.println("f1 = " + f1);
 System.out.println("f2 = " + f2);

 if (f1.equals(f2))
 System.out.println("f1 and f2 are equal");
 else
 System.out.println("f1 and f2 are not equal");

 switch (input.charAt(0))
 {
 case '+':
 f3 = f1.add(f2);
 System.out.println("f1+f2=" + f3);
 break;
 case '-':
 f3 = f1.subtract(f2);
 System.out.println("f1-f2=" + f3);
 break;
 case '*':
 f3 = f1.multiply(f2);
 System.out.println("f1*f2="+f3);
 break;
 case '/':
 f3 = f1.divide(f2);
 System.out.println("f1/f2="+f3);
 break;
 default:
 System.out.println("Illegal command: " + input );
 break;
 }
 }// end of while loop
 System.out.println("Bye");
 scan.close();
 } // end of main
}