Implementing a Stack in Go

One of the key features in go is simplicity. As a result there are a number of utilities and data structures that are common in other high-level languages that do not come with the go stdlib.

One of them is a stack. Following is a very simple implementation of a stack that uses a slice to store the data.

The following is an implementation of a simple stack that takes any kind of pointer.

import "fmt"

type Stack[T any] struct {
	stack []*T
}

func (s *Stack[T]) IsEmpty() bool {
	return len(s.stack) == 0
}

func (s *Stack[T]) Push(q *T) {
	// Add the new value to the end of the slice, which acts as the "top" of the Stack
	s.stack = append(s.stack, q)
}

func (s *Stack[T]) Pop() *T {
	if s.IsEmpty() {
		return nil
	} else {
		// Get the index of the "top" of the Stack
		idx := len(s.stack) - 1
		// Retrieve the element from the stack that we are going to "pop" and return
		retval := s.stack[idx]
		// Remove it from the underlying slice by re-slicing the slice.
		s.stack = s.stack[:idx]
		return retval
	}
}

func main() {
	i := 1
	j := 2
	s1 := &Stack[int]{}
	s1.Push(&i)
	s1.Push(&j)

	fmt.Printf("Pop! = %d\n", *s1.Pop())
	fmt.Printf("Pop! = %d\n", *s1.Pop())
}