Hash table, insert, search, delete

main.go

package main

import "fmt"

const ArraySize = 7

type HashTable struct {
	array [ArraySize]*bucket
}

type bucket struct {
	head *bucketNode
}

type bucketNode struct {
	key  string
	next *bucketNode
}

// Insert function
func (h *HashTable) Insert(key string) {
	index := hash(key)
	h.array[index].insert(key)
}

// Search function
func (h *HashTable) Search(key string) bool {
	index := hash(key)
	return h.array[index].search(key)
}

// Delete function
func (h *HashTable) Delete(key string) {
	index := hash(key)
	h.array[index].delete(key)
}

func Init() *HashTable {

	result := &HashTable{}
	for i := range result.array {
		result.array[i] = &bucket{}
	}

	return result
}

func hash(key string) int {
	sum := 0
	for _, v := range key {
		sum += int(v)
	}

	return sum % ArraySize
}

func (b *bucket) insert(k string) {
	newNode := &bucketNode{key: k}
	newNode.next = b.head
	b.head = newNode
}

func (b *bucket) search(k string) bool {
	currentNode := b.head
	for currentNode != nil {

		if currentNode.key == k {
			return true
		}

		currentNode = currentNode.next
	}

	return false
}

func (b *bucket) delete(k string) {

	if b.head.key == k {
		b.head = b.head.next
		return
	}

	previousNode := b.head
	for previousNode.next != nil {
		if previousNode.next.key == k {
			previousNode.next = previousNode.next.next
		}

		previousNode = previousNode.next
	}
}

func main() {
	hashTable := Init()
	list := []string{
		"ERIC",
		"KENNY",
		"KYLE",
		"STAN",
		"RANDY",
		"BUTTERS",
		"TOKEN",
	}

	for _, v := range list {
		hashTable.Insert(v)
	}

	fmt.Println(hashTable.Search("STAN"))
	hashTable.Delete("STAN")
	fmt.Println(hashTable.Search("STAN"))
}