Question

Towers of Hanoi (15 points) Given: n disks, all of different sizes the size of the ith disk is į .3 pegs - A, B, C the number of pegs might change in a future version of the game Inally, all the disks are stacked on peg A Requirement: Never place a larger disk on top of a smaller disk (disk 5 is larger than disk 4, etc.) Objective: Move the disks from peg A to peg C Input: n, the number of disks initially stacked on peg A; you should get n from the command line, as a command line argument; assume n 10 Output: Commands describing how the player should move the pegs Example If 3 is input then the output should be Move Peg Configuration in I from A to C 2 from A to B I from C to B from A toC I from B to A 2 from B to C I from A to C 3 2 1 3 2 1 Strategy: If there are n disks on peg A and we need to move them to peg C then we'll use peg B as a utility peg Move the top n-1 disks from A to B Move the nh disk from A to C Move the n-1 disks from B to C, using peg A as a utility OR If we must move n disks on the source peg to the dest pegusing a utility peg Move the top n-1 disks from source to utility Move the nh disk from source to dest Move the n-1 disks from utility to dest, using peg source as a utility Be sure to choose appropriate classes - it should require minimal changes if we desire to modify the problem to include any number of pegs (you should provide a flexible, extensible solution) or modify our strategy. Note your class cohesion and degree of coupling between classes (maximize cohesion, minimize coupling) You are expected to think about and correctly identify the objects in this exercise. The reasons I assigned this exercise are for you: - To get more practice programming in Java

Answer 1

//TowerOfHanoi.java
class TowerOfHanoi
{
   public void tof(char src,char dest,char spare,int n)
   {
       //according to the strategy given
      
       if(n == 1)
       {
           System.out.println(n+" from "+src + " to "+ dest);
       }
       else
       {
           //shift n-1 disks from src to utility
          
           //shift the nth disk from source to dest
           //shift the n-1 disks from utility to dest
           tof(src, spare, dest, n-1);
           System.out.println(n + " from " + src + " to " + dest);
           tof(spare, dest, src, n-1);
       }
   }
   public static void main(String args[])
   {
       //check for number of arguments given
       if(args.length == 1)
       {
           try
           {
               //convert argument to int else print error message
               int n = Integer.parseInt(args[0]);
               //create tester object to test the program
               TowerOfHanoi tester = new TowerOfHanoi();
               //call tower of hanoi recursive function of n disks
               tester.tof('A', 'C', 'B', n);
           }
           catch(Exception e)
           {
               System.out.println("Given argument is not a number");
           }
       }
       else
       {
           System.out.println("Pass number of disks n as argument");
       }
      
   }
}

//TowerOfHanoi.java class TowerOfHanoi public void tof (char src,char dest,char spare,int n) //according to the strategy given if (n- 1) 10 System.out-printin (n+" rom "+src" tO + dest) 12 13 14 15 16 17 18 19 20 21 else //shift n-1 disks from src to utility //shift the nth disc from ธ0urce to de3t //shift the n-1 disks from utility E dest tof (src, spare, dest, n-1) System.out.println (n +"Erom"+ Src"to"+dest); tof (spare, dest, src, n-1) 23 24 25 26 27 28 29 30 31 32 public statie void main (String args [) //check for number of arguments given if (args.length -1) try //convert argument to int else print error message int nInteger.parseInt (args [0]) //create tester object to test the program TowerOfHanoi tester = new TowerOfHano1();

17 18 19 20 21 //shift the n-1 disks from utility to dest tof (src, spare, dest, n-1) Sy3tem . out .printIn(n + " from + src + to tof (spare, dest, src, n-1) + dest) ; 23 24 25 26 27 28 29 30 31 32 publie statie void main (String args [i) //check for number of arguments given if (args.length-1) try //convert argument to int else print error message int nInteger.parseInt (args [o]) //create tester object to test the program TowerOfHanoi tester = new TowerOfHanoi (); //call tower of hanoi recursive function of n disks tester.tof ('A"C' B' n) 34 35 36 37 38 39 40 41 42 43 catch (Exception e) System.out.println ("Given argument is not a number"): else System.out.println("Pass number of disks n as argumenE"): 45 46 47 48 49

G4. C:\Windowslsystem32\cmd.exe java TowerOfHanoi 2 2 Pass number of disks n as argunent Uses fron A to B fron A to C java TowerOFHanoi 2 fron B to C Uses java Towe OFHanoi 3 1 fron A to C fron A to B 1 fron C to B fron A to C 1 fron B to A fron B to C fron A to C java TowerOfHanoi 3d iven argunent is not a n