queue.go

package main

import (
	"errors"
	"fmt"
)

type queue struct {
	Type string
	Q    []interface{}
	init bool
}

func (q *queue) Add(item interface{}) error {
	if !q.init {
		q.Type = fmt.Sprintf("%T", item)
		q.Q = append(q.Q, item)
		q.init = true
		return nil
	} else if fmt.Sprintf("%T", item) != q.Type {
		return errors.New("Wrong type! Queue is of type " + q.Type + ". Given type: " + fmt.Sprintf("%T", item))
	}
	q.Q = append(q.Q, item)
	return nil
}
func main() {
	myQueue := new(queue)
	if err := myQueue.Add(5); err != nil {
		fmt.Println("Error adding to queue:", err)
	}
	if err := myQueue.Add(4); err != nil {
		fmt.Println("Error adding to queue:", err)
	}
	if err := myQueue.Add("hello"); err != nil {
		fmt.Println("Error adding to queue:", err)
	}
}