class stack {
  late int _maxSize;
  late List<int> _stackArray;
  late int _top;
  stack(int size) {
    _maxSize = size;
    _stackArray = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
    _top = -1;
  }
  void push(int newPush) {
    _stackArray[++_top] = newPush;
  }

  int pop() {
    return _stackArray[_top--];
  }

  int peek() {
    return _stackArray[_top];
  }

  bool isEmpty() {
    if (_top == -1) {
      return true;
    } else {
      return false;
    }
  }

  bool isFull() {
    if (_maxSize == _top) {
      return true;
    } else {
      return false;
    }
  }
}