From 876d05d5764485a42c9dd0f87c242dc8f355523a Mon Sep 17 00:00:00 2001 From: Dimitri Sokolyuk Date: Fri, 9 Jan 2015 20:29:32 +0100 Subject: Add more helper --- stack.go | 18 ++++++++++++++++++ stack_test.go | 18 ++++++++++++++++++ 2 files changed, 36 insertions(+) diff --git a/stack.go b/stack.go index f5260ad..d4cf900 100644 --- a/stack.go +++ b/stack.go @@ -22,3 +22,21 @@ func (s *Stack) Pop() (v interface{}, ok bool) { } return v, ok } + +// Peek returns top value from Stack +func (s *Stack) Peek() interface{} { + return (*s)[len(*s) - 1] +} + +// Depth returns actual size of Stack +func (s *Stack) Depth() int { + return len(*s) +} + +// Swap swapes to top values +func (s *Stack) Swap() { + size := len(*s) + if size >= 2 { + (*s)[size-1], (*s)[size-2] = (*s)[size-2], (*s)[size-1] + } +} diff --git a/stack_test.go b/stack_test.go index 773f6cf..dec53cc 100644 --- a/stack_test.go +++ b/stack_test.go @@ -34,6 +34,24 @@ func TestMeny(t *testing.T) { } } +func TestSwap(t *testing.T) { + s := NewStack() + s.Push(1) + s.Push(2) + s.Swap() + if s.Depth() != 2 { + t.Error("Expected depth of 2") + } + a, _ := s.Pop() + b, _ := s.Pop() + if s.Depth() != 0 { + t.Error("Expected depth of 0") + } + if a != 1 || b != 2 { + t.Error("Expected swapped values") + } +} + func BenchmarkPushPopSingle(b *testing.B) { s := NewStack() for i := 0; i < b.N; i++ { -- cgit v1.2.3