Began implementing the stack and the stack stack

pkg/stack/stack.go

@@ -0,0 +1,51 @@
+package stack
+
+type Stack struct {
+	size   int
+	height int
+	data   []int
+	next   *Stack // Pointer to the next element in the stack stack
+}
+
+func NewStack() *Stack {
+	return &Stack{
+		size:   32,
+		height: 0,
+		data:   make([]int, 32),
+		next:   nil,
+	}
+}
+
+func (s *Stack) Clear() {
+	s.height = 0
+}
+
+func (s *Stack) Duplicate() {
+	if s.height > 0 {
+		s.Push(s.data[s.height-1])
+	}
+}
+
+func (s *Stack) Pop() int {
+	if s.height > 0 {
+		s.height--
+		return s.data[s.height]
+	}
+	return 0
+}
+
+func (s *Stack) Push(value int) {
+	if s.height >= s.size {
+		s.size += 32
+		s.data = append(s.data, make([]int, 32)...)
+	}
+	s.data[s.height] = value
+	s.height++
+}
+
+func (s *Stack) Swap() {
+	a := s.Pop()
+	b := s.Pop()
+	s.Push(a)
+	s.Push(b)
+}