Implementing Stack & Queue in go (golang)



First lets define the interface for Stack,

type Stack interface {
    Push(value interface{})
    Pop() (interface{}, bool)
    Peek() (interface{}, bool)
    HasNext() bool
    Len() int
}

We can use the doubly linked from "container/list" to implement our Stack,
just import "container/list"

Define a type which implements our Stack interface,

type stack struct{
    list *list.List
}


We can have constructor which returns the stack instance,
func NewStack() Queue{
    return &stack{list: list.New()}
}

We can leverage the PushFront() and Front() list methods to push values to the head
and get hold of the first element

func (this *stack) Push(value interface{}){
    this.list.PushFront(value)
}

The Front() method return a pointer to Element type in list package,
the actual value in list is stored in Element's Value field.


func (this *stack) Pop() (interface{}, bool){
    e := this.list.Front()
    if e == nil{
        return nil,false
    }
    this.list.Remove(e)
    return e.Value,true
}

similarly we can implement Peek(), we just skip the Remove() from Pop.

Len() and HasNext() can leverage the Len() method of list,

func (this *stack) Len() int{
    return this.list.Len()
}

func (this *stack) HasNext() bool{
    return this.list.Len() != 0
}





On the same lines we can implement Queue by leveraging
list.PushBack() method in Push() of Queue method.