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Summary - Dart basics

Combine main, print and comments to write your first Dart program.

Summary - Dart basics

In this group you learned the building blocks of Dart: the main entry point, output with print, comments with // and /* */, and string interpolation with $.

Combining these four concepts, you can write a real program. Now we will practice with two small tasks that use the group's concepts.

As you add variables, types and functions later, this is the skeleton your programs will grow on.

Practice Greet a user

Declare a user variable (set to Zoe). Add a // comment line above describing the program's purpose. Then print Welcome Zoe using interpolation.

Starter code

main.dart
// Add comment, user and print

Sample solution

main.dart
void main() {
  // Program that greets a user
  var user = 'Zoe';
  print('Welcome $user');
}

Expected output

Welcome Zoe

Practice Mini program

Write a program with: a // comment, void main, and inside it a variable called topic (set to Dart). Use print to output Topic: Dart (with interpolation).

Starter code

main.dart
// Add comment, topic and print

Sample solution

main.dart
void main() {
  // This is a mini program
  var topic = 'Dart';
  print('Topic: $topic');
}

Expected output

Topic: Dart

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 What is the return type of the main function?

main.dart
void main() { ... }
  • void Correct answer
  • int
  • String
  • bool

Explanation: main returns no value; that is why it is void.

2 City string

Question 
var city = 'Istanbul'; print('I live in ____city');
Answer 
var city = 'Istanbul'; print('I live in $city');

Explanation: $city embeds the city name in the string.

3 Match all concepts

Term Meaning
void main Entry point
// Comment Single-line note
$name Variable embedding
print Produces output

All lessons in Beginner

1 Dart basics

  1. What is Dart?
  2. Your first program
  3. dart run
  4. Comments
  5. String interpolation
  6. Summary - Dart basics

2 Variables

  1. var and type
  2. final
  3. const
  4. late
  5. Null safety
  6. Summary - Variables

3 Data types

  1. Integer types
  2. Floating-point types
  3. bool and String
  4. Type inference
  5. dynamic
  6. Summary - Data types

4 Project: Calculator

  1. Project design
  2. Add and subtract
  3. Multiply and divide
  4. Error handling
  5. Putting it together

5 Operators

  1. Arithmetic operators
  2. Assignment operators
  3. Comparison operators
  4. Logical operators
  5. Null-aware operators
  6. Summary - Operators

6 Strings

  1. Creating strings
  2. String interpolation
  3. length and methods
  4. substring
  5. contains and indexOf
  6. Summary - Strings

7 Conditionals

  1. The if statement
  2. else and else if
  3. switch
  4. Pattern matching
  5. Ternary
  6. Summary - Conditionals

8 Loops

  1. The for loop
  2. The while loop
  3. The do-while loop
  4. for-in
  5. break and continue
  6. Summary - Loops

9 Project: Shopping cart

  1. Cart design
  2. Adding items
  3. Calculating totals
  4. Listing the cart
  5. Putting it together

10 Lists

  1. Creating lists
  2. List access
  3. add and remove
  4. length and contains
  5. List methods
  6. Summary - Lists

11 Sets and Maps

  1. Set
  2. Set operations
  3. Map
  4. Map operations
  5. Map iteration
  6. Summary - Sets and Maps

12 Functions

  1. Defining functions
  2. Return values
  3. Arrow functions
  4. Optional parameters
  5. First-class functions
  6. Summary - Functions

13 Null safety in depth

  1. Nullable types
  2. Null-aware operators
  3. The ! operator
  4. late
  5. Null check
  6. Summary - Null safety

14 Class basics

  1. class
  2. Constructor
  3. Instance variables
  4. Methods
  5. this
  6. Summary - Class basics

15 Project: To-do CLI

  1. Task model
  2. Adding tasks
  3. Listing tasks
  4. Completing tasks
  5. Putting it together

16 Advanced string operations

  1. split and join
  2. replace
  3. trim and pad
  4. RegExp
  5. StringBuffer
  6. Summary - Advanced strings

17 Enums

  1. Defining enums
  2. Enum values
  3. Enhanced enums
  4. switch with enum
  5. Enum and patterns
  6. Summary - Enums

18 Exceptions

  1. try/catch
  2. throw
  3. finally
  4. The Exception class
  5. on clause
  6. Summary - Exceptions

19 Async basics

  1. Future
  2. async/await
  3. then
  4. Future.error
  5. Future.wait
  6. Summary - Async basics

20 Beginner final

  1. Project design
  2. Classes
  3. Collections
  4. Error handling
  5. Putting it together