Towers of Hanoi

Question

I am working on an exercise in a book which asks us to solve the Towers of Hanoi problem using recursive methods. I have come to a solution, but from what I gather after browsing the Internet when done is that my solution may not be correct. Does anyone know a better/different way to solve the problem? And does anyone have nay suggestions for improvements. (Btw, the out put is correct. It is only supposed to tell from which tower to another pegs are moving, not specifically which pegs)

Here is the code:

#include <iostream>
#include <cmath>

using namespace std;

static int counter = 0;

void ToH(int dskToMv, int cLocation, int tmpLocation, int fLocation)
{
if (dskToMv == 0);
else
{
    if (dskToMv%2!=0)
    {
        cout << cLocation << "->" << tmpLocation << endl;
        cout << cLocation << "->" << fLocation << endl;
        cout << tmpLocation << "->" << fLocation << endl;
        ToH(dskToMv-1, cLocation, fLocation, tmpLocation);
    }
    else if (dskToMv%2==0)
    {
        counter++;
        if (counter%2==0)
            cout << fLocation << "->" << cLocation << endl;
        else
            cout << cLocation << "->" << fLocation << endl;
        ToH(dskToMv-1, tmpLocation, cLocation, fLocation);
    }
}
}

int main()
{
int x, j;
cout << "Enter number of disks: ";
cin >> x;
j = pow(2.0, x-1)-1;
if (x%2==0)
    ToH(j, 1, 2, 3);
else
    ToH(j, 1, 3, 2);
return 0;
}

Is this method qualified as recursion?

Answer 1

To answer your question: yes, that is qualified as recursion. Any time a function calls itself, it is recursion.

With that being said, your code can be trimmed down substantially:

#include <iostream>

using namespace std;

void ToH(int dskToMv, int cLocation, int tmpLocation, int fLocation)
{
    if( dskToMv != 0 ) 
    {
        ToH( dskToMv-1, cLocation, fLocation, tmpLocation );
        cout << cLocation << "->" << fLocation << endl;
        ToH( dskToMv-1, tmpLocation, cLocation, fLocation );
    }
}

int main()
{
    int x;
    cout << "Enter number of disks: ";
    cin >> x;
    ToH(x, 1, 2, 3);
    return 0;
}