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)     {         // Fill in code (good to use setFraction)     }          public void setFraction(int n, int d)     {        //Fill in code ... don't forget to reduce     }          public Fraction add(Fraction op)     {         //Fill in code ... don't forget to reduce         // Algebra HINT:  a/b + c/d = (a*d + b*c)/(b*d)     }              public Fraction subtract(Fraction op)     {         //Fill in code ... don't forget to reduce         // Algebra HINT:  a/b - c/d = (a*d - b*c)/(b*d)      }             public Fraction multiply(Fraction op)     {         //Fill in code ... don't forget to reduce
        // Algebra HINT:  a/b * c/d = (a*c)/ (b*d)      }              public Fraction divide(Fraction op)     {         //Fill in code ... don't forget to reduce         // Algebra HINT:  a/b  /  c/d = (a*d)/ (b*c)      }              private void reduce()      {      // Pseudo code:      // set smaller = minimum ( abs(num), abs(denom));      // Loop through the possible divisors: 2, 3, 4, ... smaller      // For each possible divisor:       //      while (num and denom are evenly divisible by divisor)      //      {      //           num /= divisor;      //           denom /= divisor;      //           smaller /= divisor;      //      }      }            public boolean equals(Fraction f)      {         // Assuming all fractions are reduced. Fill in code      }            public String toString()      {         // Fill in code      }            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");                }  // end of main