//Author: Shawn
//Email: stepfencurryxiao@gmail.com

class ArrayStack<T> {
  //stack
  List<T> stack;
  //element of the stack
  int count;
  //size of stack
  int n;

  //Init the array stack
  ArrayStack(var n) {
    this.n = n;
    this.stack = new List<T>(n);
    this.count = 0;
  }

  //Push a item to the stack
  void push(T item) {
    if (count == n) {
      print("The stack is full\n");
    }
    stack[count] = item;
    count++;
  }

  //Pop a item from the stack
  T pop() {
    if (count == 0) {
      print("No data in the stack!\n");
    }
    T pop_data = stack[count - 1];
    stack[count - 1] = null;
    count--;
    return pop_data;
  }

  void Display() {
    print("ArrayStack: $stack\n");
  }
}

void main() {
  ArrayStack<String> array_stack = new ArrayStack<String>(6);

  array_stack.push('1');
  array_stack.push("2");
  array_stack.push('3');
  array_stack.push("4");
  array_stack.push('5');
  array_stack.push("6");

  array_stack.Display();

  var pop_data;
  pop_data = array_stack.pop();
  print("Pop $pop_data from stack\n");
  pop_data = array_stack.pop();
  print("Pop $pop_data from stack\n");
  print("Now the stock:");
  array_stack.Display();
}