func (s *VecStack) Push(value *Vec) {
	s.top = &item{value, s.top}
	s.size++
}
func (s *VecStack) Push(value *Vec) {
	s.top = &item{value, s.top}
	s.size++
}
func ( s * VecStack ) Push ( value * Vec ) { s . top = & item { value , s . top } s . size ++ }
// Push pushes a new item on top of the stack.
Push pushes a new item on top of the stack .