MODULE 5 - SHEET 1

public class RecFrac
 { public static void main(String[] args)
    { for (int i=0; i<=10; i++)
         System.out.println(f(i));
    }

   private static double f(int n)
    { if (n == 0)
         return 2.0d;
      else
         return 1.0d + 1.0d/(1.0d+f(n-1));
    }
 }

// The body of method  f  may be written more economically:
//
//  { return n==0 ? 2.0d : 1.0d+1.0d/(1.0d+f(n-1));
//  }



public class Factorial
 { public static void main(String[] args)
    { for (int i=0; i<=10; i++)
         System.out.println(fac(i));
    }

   private static int fac(int n)
    { return n==0 ? 1 : n*fac(n-1);
    }
 }



public class Hanoi
 { public static void main(String[] args)
    { move(3, "A", "B", "C");
    }

   private static void move(int n, String p, String q, String r)
    { if (n>0)
       { move(n-1, p, r, q);
         System.out.println("Move disc " + n +
                                " from peg " + p + " to peg " + r);
         move(n-1, q, p, r);
       }
    }
 }



                    MODULE 5 - SHEET 2



public class FactorialWR
 { public static void main(String[] args)
    { System.out.println(fac5());
    }

   private static int fac5()
    { return 5*fac4();
    }

   private static int fac4()
    { return 4*fac3();
    }

   private static int fac3()
    { return 3*fac2();
    }

   private static int fac2()
    { return 2*fac1();
    }

   private static int fac1()
    { return 1*fac0();
    }

   private static int fac0()
    { return 1;
    }
 }



public class HanoiWR
 { public static void main(String[] args)
    { move3("A", "B", "C");
    }

   private static void move3(String p, String q, String r)
    { move2(p, r, q);
      System.out.println("Move disc 3" +
                             " from peg " + p + " to peg " + r);
      move2(q, p, r);
    }

   private static void move2(String p, String q, String r)
    { move1(p, r, q);
      System.out.println("Move disc 2" +
                             " from peg " + p + " to peg " + r);
      move1(q, p, r);
    }

   private static void move1(String p, String q, String r)
    { move0(p, r, q);
      System.out.println("Move disc 1" +
                             " from peg " + p + " to peg " + r);
      move0(q, p, r);
    }

   private static void move0(String p, String q, String r)
    {}
 }



                    MODULE 5 - SHEET 3



// The following is a complete Java program.  The problem is to analyse
// the program and determine what it writes out WITHOUT keying the program
// in and running it.

class K
 { public static int k = 0;
 }

abstract class JJ
 { public abstract void upk();
 }

class Jack extends JJ
 { public void upk()
    { K.k += 10;
    }
 }

class Jill extends JJ
 { public void upk()
    { Jack ink = new Jack();
      ink.upk();
      K.k += 200;
    }
 }

public class UpkEtc
 { public static void main(String[] args)
    { Jack ink = new Jack();
      fred(ink, 3000);
      System.out.println("Value is " + K.k);
    }

   private static void fred(JJ uk, int n)
    { int a = 10*n;
      uk.upk();
      if (n > 1000)
       { K.k++;
         Jill ink = new Jill();
         fred(ink, n-1000);
         a += n;
       }
      K.k += a;
    }
 }