Tower of Hanoi Problem in DSA C - Build from Scratch

Tower of Hanoi Problem

📖 Scenario: Imagine you have three rods and a number of disks of different sizes which can slide onto any rod. The puzzle starts with the disks neatly stacked in ascending order of size on one rod, the smallest at the top, making a conical shape.The objective is to move the entire stack to another rod, obeying the following simple rules:Only one disk can be moved at a time.Each move consists of taking the upper disk from one of the stacks and placing it on top of another stack or on an empty rod.No disk may be placed on top of a smaller disk.

🎯 Goal: You will write a C program that uses a recursive function to solve the Tower of Hanoi problem for 3 disks. The program will print each move showing which disk moves from which rod to which rod.

📋 What You'll Learn

Create an integer variable n to represent the number of disks (3).

Create a recursive function void towerOfHanoi(int n, char from_rod, char to_rod, char aux_rod) that prints the moves.

Call the towerOfHanoi function with the correct arguments to solve the puzzle.

Print each move in the format: Move disk X from rod Y to rod Z.

💡 Why This Matters

🌍 Real World

The Tower of Hanoi problem helps understand recursion, a key concept in programming and problem solving.

💼 Career

Recursion is used in many software engineering tasks like parsing, searching, and algorithm design.

1

Create the number of disks variable

Create an integer variable called n and set it to 3 to represent the number of disks.

DSA C

# Your code here

Hint

Use int n = 3; inside the main function.

2

Write the towerOfHanoi recursive function

Write a recursive function called towerOfHanoi with parameters int n, char from_rod, char to_rod, and char aux_rod. The function should print the moves to solve the puzzle using the format Move disk %d from rod %c to rod %c\n. Implement the base case and recursive calls correctly.

DSA C

#include 

// Write the towerOfHanoi function here

int main() {
    int n = 3;
    return 0;
}

Hint

Use recursion: move n-1 disks to auxiliary rod, move the nth disk, then move n-1 disks to target rod.

3

Call the towerOfHanoi function in main

Inside the main function, call towerOfHanoi with arguments n, 'A', 'C', and 'B' to solve the puzzle from rod A to rod C using rod B as auxiliary.

DSA C

#include 

void towerOfHanoi(int n, char from_rod, char to_rod, char aux_rod) {
    if (n == 1) {
        printf("Move disk 1 from rod %c to rod %c\n", from_rod, to_rod);
        return;
    }
    towerOfHanoi(n - 1, from_rod, aux_rod, to_rod);
    printf("Move disk %d from rod %c to rod %c\n", n, from_rod, to_rod);
    towerOfHanoi(n - 1, aux_rod, to_rod, from_rod);
}

int main() {
    int n = 3;
    // Call towerOfHanoi here
    // Your code here
}

Hint

Call towerOfHanoi with n, 'A', 'C', 'B'

4

Print the moves to solve Tower of Hanoi

Run the program to print the sequence of moves to solve the Tower of Hanoi problem for 3 disks. The output should show each move in the format Move disk X from rod Y to rod Z.

DSA C

#include 

void towerOfHanoi(int n, char from_rod, char to_rod, char aux_rod) {
    if (n == 1) {
        printf("Move disk 1 from rod %c to rod %c\n", from_rod, to_rod);
        return;
    }
    towerOfHanoi(n - 1, from_rod, aux_rod, to_rod);
    printf("Move disk %d from rod %c to rod %c\n", n, from_rod, to_rod);
    towerOfHanoi(n - 1, aux_rod, to_rod, from_rod);
}

int main() {
    int n = 3;
    towerOfHanoi(n, 'A', 'C', 'B');
    // Print output
    // Your code here
}

Hint

Run the program and check the printed moves.