stack.go

package main

import (
    "fmt"
)

type Node struct {
    Value int
}

/*
func (n *Node) String() string {
    return fmt.Sprint(n.Value)
}
*/

// NewStack returns a new stack.
func NewStack() *Stack {
    return &Stack{}
}

// Stack is a basic LIFO stack that resizes as needed.
type Stack struct {
    nodes []*Node
    count int
}

// Push adds a node to the stack.
func (s *Stack) Push(n *Node) {
    s.nodes = append(s.nodes[:s.count], n)
    s.count++
}

// Pop removes and returns a node from the stack in last to first order.
func (s *Stack) Pop() *Node {
    if s.count == 0 {
        return nil
    }
    s.count--
    return s.nodes[s.count]
}

func main() {
    s := NewStack()
    s.Push(&Node{1})
    s.Push(&Node{2})
    s.Push(&Node{3})
    fmt.Println(s.Pop(), s.Pop(), s.Pop())
}