HANOI 1-C

 

                                    Solving Tower of Hanoi problem with n disks

 The Tower of Hanoi problem is a classic example of recursion and stack operations. The goal is to move n disks from the source peg to the destination peg, using an auxiliary peg, while obeying the following rules:

Explanation:

Function tower(n, from, aux, to):

• Moves n disks from from peg to to peg using aux peg.

• Recursively breaks the problem into smaller moves:

  1. Move n-1 disks from from → aux

  2. Move the largest disk (n) from from → to

  3. Move n-1 disks from aux → to

• main() function:

• Takes the number of disks (n) as input.

• Calls tower() to print all moves.

• Calculates total moves using formula 2^n - 1 with pow().

ERROR?

You're getting this error because the pow() function (used to calculate total moves) is part of the math library, and the math library (libm) is not linked by default in GCC.

To Fix This:

Use the -lm flag at the end of your gcc command to link the math library.

gcc han.c -o abcd -lm

Why?

• pow() is defined in the <math.h> header but implemented in the math library.

• You must explicitly link it using -lm.

Re-run Your Program:

After compiling successfully:

./abcd

Let me know if you want a version of the program that avoids using pow() entirely (using just integer math).

Program:

#include <stdio.h>

#include <math.h>

// Recursive function to solve Tower of Hanoi

void tower(int n, char from_peg, char aux_peg, char to_peg) {

if (n == 1) {

printf("Move disk %d from %c peg to %c peg\n", n, from_peg, to_peg);

return;

}

// Move n-1 disks from source to auxiliary

tower(n - 1, from_peg, to_peg, aux_peg);

// Move the nth disk to destination

printf("Move disk %d from peg %c to %c peg\n", n, from_peg, to_peg);

// Move n-1 disks from auxiliary to destination

tower(n - 1, aux_peg, from_peg, to_peg);

}

int main() {

int n;

printf("Enter the number of disks: ");

scanf("%d", &n);

tower(n, 'A', 'B', 'C'); // A: source, B: auxiliary, C: destination

printf("Total number of moves = %.0f\n", pow(2, n) - 1);

return 0;

}

OUTPUT: