Solution 3: Go Generics

package main
import (
	"fmt"
)
type node[T any] struct {
	Data T
	next *node[T]
}
type list[T any] struct {
	start *node[T]
}
func (l *list[T]) add(data T) {
	n := node[T]{
		Data: data,
		next: nil,
	}
	if l.start == nil {
		l.start = &n
		return
	}
	if l.start.next == nil {
		l.start.next = &n
		return
	}
	temp := l.start
	l.start = l.start.next
	l.add(data)
	l.start = temp
}
func (l *list[T]) search(data T, equal func(T, T) bool) bool {
	current := l.start
	for current != nil {
		if equal(current.Data, data) {
			return true
		}
		current = current.next
	}
	return false
}
func (l *list[T]) delete(data T, equal func(T, T) bool) {
	if l.start == nil {
		return
	}
	if equal(l.start.Data, data) {
		l.start = l.start.next
		return
	}
	current := l.start
	var prev *node[T] = nil
	for current != nil {
		if equal(current.Data, data) {
			prev.next = current.next
			return
		}
		prev = current
		current = current.next
	}
}
func main() {
	var myList list[int]
	fmt.Println(myList)
	myList.add(12)
	myList.add(9)
	myList.add(3)
	myList.add(9)
	// Print all elements
	current := myList.start
	for current != nil {
		fmt.Println("*", current.Data)
		current = current.next
	}
	// Search for an element
	equalFunc := func(a, b int) bool { return a == b }
	fmt.Println("Search for 3:", myList.search(3, equalFunc))
	fmt.Println("Search for 7:", myList.search(7, equalFunc))
	// Delete an element
	myList.delete(9, equalFunc)
	fmt.Println("After deleting 9:")
	current = myList.start
	for current != nil {
		fmt.Println("*", current.Data)
		current = current.next
	}
}