First CLI Program.md

Build a "Tower of Hanoi" program in Go

Let's understand through this program, mechanics of writing and compiling programs in Go.

First create a file named tower_of_hanoi.go.Then in the main package create the function main. Now print out the line "Tower of Hanoi!".

package main

import (
	"fmt"
	"time"
)
func main() {
	fmt.Println("Tower of Hanoi!")
	}

Firstly, let's understand the what is Tower of Hanoi and logic to solve.

Introduction: The game "Towers of Hanoi" uses three rods. A number of disks is stacked in decreasing order from the bottom to the top of one rod, i.e. the largest disk at the bottom and the smallest one on top.
Problem Statement: You've to move tower of disks from one rod to another rod.
Constraints:

• Only one disk must be moved at a time.
• Only the most upper disk from one of the rods can be moved during a single move.
• It can be put on another rod, if this rod is empty or if the most upper disk of this rod is larger than the one which is moved.
  Let visualize using below infographic! Now it's code.

package main

import (
	"fmt"
	"time"
)

const Towers = 3
const Disks = 5

type Hanoi [Towers][]int

func main() {
        fmt.Println("Tower of Hanoi!")
	var state Hanoi
	state.init(Disks)
	state.move(Disks, 0, 1, 2)
}

func (h *Hanoi) init(n int) {
	h[0] = make([]int, n)
	for i := range h[0] {
		h[0][i] = n - i
	}
	h.print()
}

func (h *Hanoi) move(n, a, b, c int) {
	if n <= 0 {
		return
	}
	h.move(n-1, a, c, b)
	disk := h[a][len(h[a])-1]
	h[a] = h[a][:len(h[a])-1]
	h[c] = append(h[c], disk)
	h.print()
	h.move(n-1, b, a, c)
}

func (h *Hanoi) print() {
	fmt.Print("\f")
	for i := Disks; i >= 0; i-- {
		for j := 0; j < Towers; j++ {
			if i == 0 {
				fmt.Print("_/||\\_")
			} else if len(h[j]) >= i {
				fmt.Printf("  %02d  ", h[j][i-1])
			} else {
				fmt.Print("  ||  ")
			}
		}
		fmt.Println()
	}
	fmt.Println()
	time.Sleep(time.Second / 5)
}