Constructors and named parameters in Flutter - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a constructor with a named parameter called 'name'.

Flutter

class Person {
  String name;
  Person([1]);
}

Drag options to blanks, or click blank then click option'

Arequired this.name

Bthis.name

Cname

Dthis.name = name

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to use curly braces for named parameters.

Not marking the parameter as required when needed.

The constructor uses a named parameter with required this.name to ensure the 'name' is passed when creating an object.

2fill in blank

medium

Complete the constructor to accept an optional named parameter 'age' with a default value of 18.

Flutter

class Person {
  int age;
  Person([1]);
}

Drag options to blanks, or click blank then click option'

Athis.age = 18

Bthis.age = 0

Cthis.age = 18, required

Dthis.age

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to mark default parameters as required.

Not assigning a default value properly.

Using this.age = 18 in the named parameter sets a default value of 18 if no value is provided.

3fill in blank

hard

Fix the error in the constructor to correctly assign the named parameter 'title' to the field.

Flutter

class Book {
  String title;
  Book([1]) {
    this.title = title;
  }
}

Drag options to blanks, or click blank then click option'

AString title

Brequired this.title

Cthis.title

Dtitle

Attempts:

3 left

💡 Hint

Common Mistakes

Declaring parameter without 'this.' and trying to assign manually.

Omitting 'required' for mandatory parameters.

Using required this.title in the constructor parameters automatically assigns the value to the field.

4fill in blank

hard

Fill both blanks to create a constructor with a named parameter 'color' that is optional and has a default value 'blue'.

Flutter

class Car {
  String color;
  Car([1] [2]);
}

Drag options to blanks, or click blank then click option'

Athis.color = 'blue',

Brequired

Cthis.color

Dcolor

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'required' with default values.

Not assigning default value properly.

The constructor uses this.color = 'blue' as an optional named parameter with a default value, and this.color to assign it.

5fill in blank

hard

Fill all three blanks to define a constructor with named parameters 'width' and 'height' both required, and an optional 'color' with default 'red'.

Flutter

class Rectangle {
  int width;
  int height;
  String color;
  Rectangle([1] [2] [3]);
}

Drag options to blanks, or click blank then click option'

Arequired this.width,

Brequired this.height,

Cthis.color = 'red',

Dthis.color

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting 'required' for mandatory parameters.

Not setting default value for optional parameters.

The constructor requires width and height using required this.field, and sets an optional color with a default value.