A stack implemented in Go using a linkedlist data structure

linked_list_stack.go

package main

import (
	"errors"
	"fmt"
	"log"
)

type ListNode struct {
	number int
	next   *ListNode
}

type IntStack struct {
	head *ListNode
}

func (i *IntStack) Push(value int) {
	if i.head == nil {
		i.head = &ListNode{number: value, next: nil}
	} else {
		i.head = &ListNode{number: value, next: i.head}
	}
}

func (i *IntStack) Pop() int {
	if i.head == nil {
		log.Panic(errors.New("stack is empty"))
	}

	value := i.head.number
	i.head = i.head.next
	return value
}

func (i *IntStack) Peek() int {
	if i.head == nil {
		return -1
	}

	return i.head.number
}

func main() {

	st := IntStack{}
	st.Push(1)
	st.Push(2)
	st.Push(3)
	st.Push(4)

	fmt.Println("popped: ", st.Pop())
	fmt.Println("popped: ", st.Pop())
	fmt.Println("popped: ", st.Pop())
	fmt.Println("on stack: ", st.Peek())
	fmt.Println("popped: ", st.Pop())
	fmt.Println("on stack: ", st.Peek())

	// empty stack error
	fmt.Println(st.Pop())
}