Tower of hanoi in Kotlin

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What is Tower of Hanoi and How it works ?

The Tower of Hanoi is a mathematical puzzle consisting of three rods and a number of disks of different sizes, which can slide onto any rod. The puzzle starts with the disks in a neat stack in ascending order of size on one rod, the smallest at the top, thus making a conical shape.

The objective of the puzzle is to move the entire stack to another rod, obeying the following simple rules:

  1. Only one disk can be moved at a time.
  2. 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.
  3. No disk may be placed on top of a smaller disk.

The puzzle is often used to teach computer programming, algorithm design, and recursion. It is also a popular puzzle among mathematicians and puzzle enthusiasts. The minimum number of moves required to solve a Tower of Hanoi puzzle is 2^n – 1, where n is the number of disks.

Steps to create Tower of Hanoi in Kotlin.

Step 1: Create a function which will take 4 argument x, A, B, C. where x is number of disks, A is a source rod, B is a auxiliary rod and C is destination rod.

Kotlin
fun toh(x: Int, A: String, B: String, C: String){

}

Step 2: how check if x = 1 the print move a -> c and terminate the program

Step 3: Else call toh with x = x-1 and change the rod names

Kotlin
fun toh(x: Int, A: String, B: String, C: String){
    if(x==1) {
        println("$A to $C")
        return
    }
    toh(x-1,A,C,B)
    println("$A to $C")
    toh(x-1,B,A,C)
}

Step 4: Call the function from main function by providing the each value

Kotlin
fun main(){
    val x = 3
    toh(x,"A","B","C")
}
fun toh(x: Int, A: String, B: String, C: String){
    if(x==1) {
        println("$A to $C")
        return
    }
    toh(x-1,A,C,B)
    println("$A to $C")
    toh(x-1,B,A,C)
}

You can run the code by clicking on play button on the right top of the final code.

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