How to define a Stack in dartPad?

Question

import 'package:starter/stack.dart';

void main() {
print (calculation("(2+2*6"));
}

 calculation(expression){
   var tokens = expression.split(" ");
   Stack values = Stack();
   Stack ops = Stack();
}

note that if I remove the import (first line) I get this error message "The function 'Stack' isn't defined." and when I add the import the error message is "Unsupported import(s): (package:starter/stack.dart)".

score 1 · Accepted Answer · answered Oct 24 '22 at 08:36

1

Stack is not built in the dart. But we can make a generic class with its methods(get, push, pop) implementation using list.

class CustomStack<T> {
  final _list = <T>[];

  void push(T value) => _list.add(value);

  T pop() => _list.removeLast();

  T get top => _list.last;

  bool get isEmpty => _list.isEmpty;
  bool get isNotEmpty => _list.isNotEmpty;

  @override
  String toString() => _list.toString();
}

Just put the above class somewhere in the project lib directory. And use it like.

CustomStack<String> plates = CustomStack();
//Add plates into the stack
  plates.push("Plate1");
  plates.push("Plate2");
  plates.push("Plate3");
// delete the top plate
  plates.pop();

answered Oct 24 '22 at 08:36

Kamlendra Pandey

346
5
8

thank you so much, how can we get the length of plates? – Ayz Oct 24 '22 at 09:05
@AymieChalouhy we have to add one more get method called length, in which we can return the length of the list. I will edit the above answer. – Kamlendra Pandey Oct 25 '22 at 04:34
1

or simply add the below code anywhere in the CustomStack class >>>>>> int get length => _list.length; – Kamlendra Pandey Oct 25 '22 at 04:38

How to define a Stack in dartPad?

1 Answers1