week1

Labs – week 1

If your IDE doesn't detect the project files, run the following in the terminal:

cd labs/week1
dart pub get

Running the exercises

From IntelliJ or Android Studio

1. In the top bar, select the Week 1 run configuration.
2. Click the green play button (Run).

From VS Code

1. Open the "Run and Debug" view from the sidebar.
2. Select the Week 1 run configuration.
3. Click the green play button (Run).

From the terminal

1. Navigate to the labs/week1 directory.
2. Execute dart run.

Exercise parts

Note

Make sure to add print statements to your solutions (in the partX functions) to present your progress.

1. Hello, Dart!

1. Create a simple Q&A program.

   1. Ask the user (stdin) about their name and favorite color. You can add more questions.
   2. Then, print a greeting using their data.

2. Print a triangle of asterisks, something like this:

   *
   **
   ***
   ****
   *****
   ******
   *******
   

2. Collections

package:collection might be useful.

1. Lists & sets
   1. Create a list of 30 random integers between 0 and 20 (use the Random class).
   2. Sort the list in descending order.
   3. Filter the list, so that it contains only numbers divisible by 3.
   4. Remove duplicates from the list (i.e., make a set out of it).
   5. Print each element, its index in the list, and whether it is even or odd.
2. Maps
   1. Create a collection of Strings (e.g., names, cities, etc.).
   2. Create a map that maps each string to its length.
   3. Group the elements by their first letter.

3. Object-oriented programming

1. Define a following class hierarchy of animals. All animals have an age and a name. Their description should include these two fields.

   Make sure that Dog, Cat and Cow are the only animals allowed in this hierarchy.

   ---
   title:
   ---
   classDiagram
       class Animal {
           int age
           String name
           get String description
           void makeSound()*
       }
   
       Animal <|-- Dog
       class Dog {
           String color
       }
   
       Animal <|-- Cat
       class Cat {
           String color
       }
   
       Animal <|-- Cow
       class Cow {
           int weight
       }
   

   Loading

   Example usage:

   final myDog = Dog('Rex', age: 3, color: 'brown');
   final aCow = Cow('Betsy', age: 5, weight: 500);

2. Create a list of various animals. Iterate over this list and make every animal make a sound. Also, for each animal, print its additional fields like color or weight.

   Use pattern matching to simplify matching subclasses and reading their properties.

4. Generics

1. Define a generic Container class that holds a single value.

   Example usage:

   final intContainer = Container<int>(42);
   final stringContainer = Container<String>('Hello, world!');

   Make sure null cannot be stored in the container, i.e. the type parameter is not nullable:

   // This shouldn't compile
   final invalid = Container<String?>(null);

2. Create a list of various containers. Then loop over them: if the contained value is a number, print its square. If it's a string, print its length.

5. Records

1. Define a function called generate that returns a random triple of integers.

2. Define a function called transform that accepts a triple of integers and:

   1. If all values are 0, returns "All zeros!".
   2. If the first value is greater than 10 and the second one is equal to 5, returns the third one.
   3. If the first value is even, returns the first and second values.
   4. Else, returns the entire triple.

   Don't use if statements in this function.

   Try to define transform with the arrow syntax => ....

3. Define a function called randomize that returns a random record of:

   • Two integers x and y
   • A boolean enabled
   • A double temperature

4. Read the four values from randomize into variables inside part5 without creating any additional variables or using property access (i.e. obj.prop).