Thread: The Towers of Hanoi

  1. #1
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    The Towers of Hanoi

    I have to write a program that the user enters the number of disks from tower 1 to tower 3. The rules are: only one disk can be moved at any time and no disk can be placed on top of a disk with a smaller diameter. All i have left to do is change my code so that it for each move it says e.g. disk 1 from tower 1 to tower 3. Also I need to print out how many moves it took. If you can help me, then thank you. Here is what I have:

    #include <stdio.h>
    void tower(int, int, int, int);

    main()
    {
    int n;

    printf("Enter the starting number of disks: ");
    scanf("%d", &n);
    tower(n, 1, 3, 2);

    return 0;
    }

    void tower(int c, int start, int end, int temp)
    {
    if (c == 1) {
    printf("%d --> %d\n", start, end);
    return;
    }

    tower(c - 1, start, temp, end);

    printf("%d --> %d\n", start, end);

    tower(c - 1, temp, end, start);
    }

  2. #2
    Registered User jasrajva's Avatar
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    use a global variable
    int i;

    and incrment it each time you printf()
    jv

  3. #3
    Skunkmeister Stoned_Coder's Avatar
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    Code:
    #include <iostream> 
    using namespace std;
    void towers(int, int, int, int); 
    
    int level[3]; 
    int main() 
    { 
    int n; 
    cout << "Enter the number of disks on peg # 1: " << endl; 
    cin >> n;
    level[0] = n; 
    level[1] = 0; 
    level[2] = 0; 
    towers(1, 3, 2, n);
    return 0; 
    } 
    
    void towers(int fromTower, int toTower, int auxTower, int n) {
    if (n==1) {
    cout << "Move disk 1 from level " << level[fromTower - 1]
    << " of tower " << fromTower << " to level " 
    << level[toTower-1] + 1 << " of tower " << toTower << endl;
    level[fromTower - 1] -= 1;
    level[toTower - 1] += 1; 
    }
    else 
    {
    towers(fromTower, auxTower, toTower, n-1);
    cout << "Move disk " << n << " from level " << level[fromTower - 1]
    << " of tower " << fromTower << " to level "
    << level[toTower - 1] + 1 << " of tower " << toTower << endl;
    level[fromTower - 1] -= 1; 
    level[toTower - 1] += 1; 
    towers(auxTower, toTower, fromTower, n-1);
    } 
    }
    now you add the move counting....
    Free the weed!! Class B to class C is not good enough!!
    And the FAQ is here :- http://faq.cprogramming.com/cgi-bin/smartfaq.cgi

  4. #4
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    Stone_Coder
    What is the code in C not C++?

  5. #5
    Skunkmeister Stoned_Coder's Avatar
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    yeah i just noticed i was on the c board and not the c++ board sorry....

    cin>> is equivalent to scanf()
    cout<< is equivalent to printf()

    you will need header <stdio.h> not <iostream>.... sorry

    so...
    Code:
    #include<stdio.h>
    void towers(int, int, int, int); 
    
    int level[3]; 
    int main() 
    { 
    int n; 
    printf("Enter the number of disks on peg # 1: " );
    fflush(stdout); 
    scanf("%d",&n);
    printf("\n");
    level[0] = n; 
    level[1] = 0; 
    level[2] = 0; 
    towers(1, 3, 2, n);
    return 0; 
    } 
    void towers(int fromTower, int toTower, int auxTower, int n) 
    {
    if (n==1) 
    {
    printf("Move disk 1 from level %d of tower %d to level %d of tower %d\n",level[fromTower - 1],fromTower,level[toTower-1] + 1,toTower );
    level[fromTower - 1] -= 1;
    level[toTower - 1] += 1; 
    }
    else 
    {
    towers(fromTower, auxTower, toTower, n-1);
    printf("Move disk %d from level %d of tower %d to level %d of tower %d\n",n,level[fromTower - 1],fromTower,level[toTower-1] + 1,toTower );
    level[fromTower - 1] -= 1; 
    level[toTower - 1] += 1; 
    towers(auxTower, toTower, fromTower, n-1);
    } 
    }
    Free the weed!! Class B to class C is not good enough!!
    And the FAQ is here :- http://faq.cprogramming.com/cgi-bin/smartfaq.cgi

  6. #6
    Former Member
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    I made a nice program in VB which does this Exactly like you do it here (I mean the recursive solution, but more graphical, of course, it's somewhere in this board (C board, I think)

    If you do some math, you will find out that for n discs, the minimum amount of moves needed is

    (2^n)-1

    Oskilian

  7. #7
    free(me);
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    ...

    Now all that is left to do is find the iterative solution

    adios,
    biterman.
    Do you know how contemptous they are of you?

  8. #8
    Registered User zahid's Avatar
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    /*t_of_hanoi.c, [email protected]*/

    #include<stdio.h>
    int shift(int, int, int);
    static int move=0;

    int main()
    {
    int disk;
    printf("Number of disk:");
    scanf("%d",&disk);

    /*____1,2,3 are the towers*/
    shift_disk(1,3,disk);

    printf("\nAll disks shifted: %d Move\n",move);
    printf("Successfully done!!\n\n");

    getch(); /*Comment the line if not from DOS/WINDOWS*/

    return 0;
    }


    int shift_disk(int from, int to, int disk)
    {
    int new_to;

    new_to= from+to;
    new_to = 6-new_to;

    if(disk==0) return 0;

    /*____first move all except the last to the mid tower*/
    shift_disk(from, new_to, disk-1);

    printf("%4d: Move a disk from tower %d to %d\n",++move,from,to);

    /*____Then move all disks from mid tower to destination tower*/
    shift_disk(new_to, to, disk-1);

    return 0;

    }
    Last edited by zahid; 01-07-2002 at 07:09 AM.
    [ Never code before desk work ]
    -------------------------------------:-->
    A man who fears Nothing is the man who Loves Nothing
    If you Love Nothing, what joy is there in your life.
    =------------------------------------------------------= - I may be wrong.

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