// Stack Linked-List with standard library (Container/List)
// description: based on `geeksforgeeks` description Stack is a linear data structure which follows a particular order in which the operations are performed.
// The order may be LIFO(Last In First Out) or FILO(First In Last Out).
// details:
// Stack Data Structure : https://www.geeksforgeeks.org/stack-data-structure-introduction-program/
// Stack (abstract data type) : https://en.wikipedia.org/wiki/Stack_(abstract_data_type)
// author [Milad](https://github.com/miraddo)
// see stacklinkedlist.go, stackarray.go, stack_test.go
package stack
import (
"container/list"
"fmt"
)
// SList is our struct that point to stack with container/list.List library
type SList struct {
stack *list.List
}
// Push add a value into our stack
func (sl *SList) Push(val interface{}) {
sl.stack.PushFront(val)
}
// Peak is return last value that insert into our stack
func (sl *SList) Peak() (interface{}, error) {
if !sl.Empty() {
element := sl.stack.Front()
return element.Value, nil
}
return "", fmt.Errorf("stack list is empty")
}
// Pop is return last value that insert into our stack
//also it will remove it in our stack
func (sl *SList) Pop() (interface{}, error) {
if !sl.Empty() {
// get last element that insert into stack
element := sl.stack.Front()
// remove element in stack
sl.stack.Remove(element)
// return element value
return element.Value, nil
}
return "", fmt.Errorf("stack list is empty")
}
// Length return length of our stack
func (sl *SList) Length() int {
return sl.stack.Len()
}
// Empty check our stack has value or not
func (sl *SList) Empty() bool {
// check our stack is empty or not
// if is 0 it means our stack is empty otherwise is not empty
return sl.stack.Len() == 0
}