stack.go

package stack

// Stack is a LIFO collection.
//
// Concurrency: not safe for concurrent use.
type Stack[T any] struct {
	elements []T
}

func (s *Stack[T]) Push(element T) {
	s.elements = append(s.elements, element)
}

func (s *Stack[T]) Pop() (T, bool) {
	var zero T
	l := len(s.elements)
	if l == 0 {
		return zero, false
	}

	ret := s.elements[l-1]
	s.elements[l-1] = zero
	s.elements = s.elements[:l-1]
	return ret, true
}

stack_test.go

package stack_test

import (
	"stack"
	"testing"
)

func TestStack(t *testing.T) {
	s := &stack.Stack[int]{}
	s.Push(1)
	s.Push(2)
	s.Push(3)

	if num, _ := s.Pop(); num != 3 {
		t.Errorf("Expected 3, got: %v", num)
	}
	if num, _ := s.Pop(); num != 2 {
		t.Errorf("Expected 2, got: %v", num)
	}
	if num, _ := s.Pop(); num != 1 {
		t.Errorf("Expected 1, got: %v", num)
	}
	if _, ok := s.Pop(); ok == true {
		t.Errorf("Expected false, got: %v", ok)
	}

}