Tower of Hanoi Problem

So, I tried to implement code that solves the Tower of Hanoi Problem (which I had previously used in python), and it sort of worked, but outputted

Move disk 1 from tower 65 to tower 67

Move disk 2 from tower 65 to tower 67

Move disk 1 from tower 66 to tower 65

for towers_of_hanoi(2,'A','B','C') (the problem being that it outputted 65 instead of A, 66 for B and 67 for C which I'm guessing is ASCII)

How would I avoid this issue while keeping similar code? Or do i need to use something like vertcat? Please help. My code is below:

    % 
  function towers_of_hanoi(n,A,B,C)
    if (n~=0)
        towers_of_hanoi(n-1,A,B,C);
        disp(sprintf('Move disk %d from tower %d to tower %d',[n A C]));
        towers_of_hanoi(n-1,B,C,A);
    end
end

Answer 1

[Walter Roberson]

I already gave the solution in your previous posting on this topic, which you appear to have deleted.

Use %s instead of %d when you want to output strings.

[SB]

I actually tried that( I forgot to update the code), but when I do

    %
function towers_of_hanoi(n,A,B,C)   
 if (n~=0)
        towers_of_hanoi(n-1,A,B,C);
        disp(sprintf('Move disk %d from tower %s to tower %s',[n A C]));
        towers_of_hanoi(n-1,B,C,A);
    end
end

It outputs:

Move disk 1 from tower AC to tower

Move disk 2 from tower AC to tower

Move disk 1 from tower BA to tower

Instead of the proper solution.

[Walter Roberson]

disp(sprintf('Move disk %d from tower %s to tower %s',n, A, C))

Alternately,

fprintf('Move disk %d from tower %s to tower %s',n, A, C);

which is the same thing except with the display of the string built-in.

Answer 2

[Chenyang Huang]

function towers_of_hanoi(n,A,C,B)
  if (n~=0)
      towers_of_hanoi(n-1,A,B,C);
      disp(sprintf('Move disk %d from tower %c to tower %c',[n A C]));
      towers_of_hanoi(n-1,B,C,A);
  end
end

 ------
>> towers_of_hanoi(3,'A','C','B')

[Walter Roberson]

There is no apparent question or comment there?

I do not recommend this code; it relies upon using [] to concatenate a number and two characters, and then relies upon MATLAB pulling them apart again. There is no good reason to use [n A C] there instead of n, A, C as separate arguments. And you might as well use %s . In fact you might as well use the fprintf() that I showed:

fprintf('Move disk %d from tower %s to tower %s',n, A, C);

Answer 3

[Sarvesh Agarwal]

How to find the no. of moves by a particular disc. Let's just say for total 10 disks what are the no. of moves by 4th disk provided topmost is 1st disk. Thanks in advance.

[Walter Roberson]

https://en.wikipedia.org/wiki/Tower_of_Hanoi

With 10 disks, the largest disk (#10) moves 2^0 times, the next largest (#9) moves 2^1 times, the next largest (#8) moves 2^2 times, and so on.

Answer 4

[Kelly Tatiana Acosta Contreras]

%

function towers_of_hanoi(n,A,B,C)

if (n~=0)

towers_of_hanoi(n-1,A,B,C);

disp(sprintf('Move disk %d from tower %d to tower %d',[n A C]));

towers_of_hanoi(n-1,B,C,A);

end

end

Answer 5

[Jerome Bastien]

Caution, there is a small mistake in the answears of Chenyang Huang : the correct line is

disp(sprintf('Move disk %d from tower %d to tower %d',[n A C]));

and no

disp(sprintf('Move disk %d from tower %c to tower %c',[n A C]));

The final correct code is :

function towers_of_hanoi(n,A,C,B)

if (n~=0)

towers_of_hanoi(n-1,A,B,C);

% Erreur

% disp(sprintf('Move disk %d from tower %c to tower %c',[n A C]));

disp(sprintf('Move disk %d from tower %d to tower %d',[n A C]));

towers_of_hanoi(n-1,B,C,A);

end

end