stack

type Stack interface {
	// push a data into stack
	Push(v interface{})
	// pop last data
	Pop() (interface{}, bool)
	// pop many of data
	PopMany(count int64) ([]interface{}, bool)
	// pop all data
	PopAll() ([]interface{}, bool)
	// peek last data
	Peek() (interface{}, bool)
	// get length of stack
	Length() int64
	// judge stack's lenght if 0
	IsEmpty() bool
}