sync lock

...

sync lock

package main

import (
	"fmt"
	"sync"
)

type Item interface {
}

type ItemStack struct {
	items []Item
	lock  sync.RWMutex
}

func NewStack() *ItemStack {
	s := &ItemStack{}
	s.items = []Item{}
	return s
}

func (s *ItemStack) Print() {
	fmt.Println(s.items)
}

func (s *ItemStack) Push(t Item) {
	s.lock.Lock()
	s.items = append(s.items, t)
	s.lock.Unlock()
}
func (s *ItemStack) Pop() (item Item) {
	s.lock.Lock()
	defer s.lock.Unlock()
	sl := len(s.items)
	if sl == 0 {
		return nil
	}
	item = s.items[sl-1]
	s.items = s.items[0 : sl-1]
	return item
}

func main()  {
	stack := NewStack()
	stack.Print()
	stack.Push(3)
	stack.Print()
	stack.Push(5)
	stack.Print()
	stack.Pop()
	stack.Print()
	stack.Pop()
	stack.Print()
}

...

sort

package main

import (
	"fmt"
	"sort"
)

func main()  {
	intlist := [] int{2,3,8,5,6,7,4,9}
	sort.Sort(sort.Reverse(sort.IntSlice(intlist)))

	float8list := []float64{4.2,5.2,6.2,7.2,1.2}
	sort.Sort(sort.Reverse(sort.Float64Slice(float8list)))

	stringlist := []string{"a","b","e","d","c"}
	sort.Sort(sort.Reverse(sort.StringSlice(stringlist)))
	fmt.Printf("%v\n%v\n%v",intlist,float8list,stringlist)
}