Basic Dart Programming Language 2023.pdf

Dart Programming
Language
- Lim Phanith - 21 March 2023

Content Outline
I. Introduction
II. Variable
III. List and Mapping
IV. Control Flow
V. Function
VI. Classes
VII. Object-Oriented Programming
VIII. Asynchronous
IX. Practice
2

I. Introduction
Dart is a general purpose programming language developed by Google. You can
use it to develop web, server, desktop and mobile applications for iOS and
Android. It’s easy to learn (especially if you read this book) and also has great
tooling support.
3

II. Variables & Constants 🧮
int n1 = 10; stores integers (whole numbers), without decimals, such
as 123 or -123
double n2 = 12.23; stores ﬂoating point numbers, with decimals, such as
19.99 or -19.99
String n3 = 'myString'; stores text, such as "Hello World". String values are
surrounded by double quotes
bool n4 = true; stores values with two states: true or false
var n5 = 12; The var keyword says to Dart, “Use whatever type is
appropriate.”
dynamic n6 = '12112';
n5 = 12.12;
n5 = 12;
lets you assign any data type you like to your variable
num n7 = 12.5;
num n7 = 12;
store both an integer and ﬂoating-point value
const n10 = 10; constants when compile-time
final n11 = n1 + n2; constants when runtime
4

III. List and Mapping 🧮
void main() {
List<int> myList = [1, 3, 5, 1, 5, 8, 9];
myList.forEach((element) {
print(element);
});
myList.removeAt(5);
myList.sort();
}
void main() {
Map<String, dynamic> student = {
'id': 12323,
'name': 'Phanith',
'age': 20,
'address': '123 Main St',
'phone': '555-555-5555'
};
print(student['name']);
./Modify the student map to add a new key/value pair
student['name'] = 'John';
./forEach loop to print out all the key/value pairs
student.forEach((key, value) {
print('$key: $value');
});
./Remove the phone key/value pair
student.clear();
}
List
Mapping
5

IV. Control Flow 🕹
const animal = 'Fox';
if (animal == 'Cat' .| animal .= 'Dog') {
print('Animal is a house pet.');
} else {
print('Animal is not a house pet.');
}
If else statement
const trafficLight = 'yellow';
var command = '';
if (trafficLight .= 'red') {
command = 'Stop';
} else if (trafficLight .= 'yellow') {
command = 'Slow down';
} else if (trafficLight .= 'green') {
command = 'Go';
} else {
command = 'INVALID COLOR!';
}
print(command);
If else-if statement
6

const number = 3;
switch (number) {
case 0:
print('zero');
break;
case 1:
print('one');
break;
case 2:
print('two');
break;
case 3:
print('three');
break;
case 4:
print('four');
break;
default:
print('something else');
}
switch statement Noted:
switch statement is usually faster than a series of
if-else statements when there are many cases to
check. This is because a switch statement uses a table
lookup to determine which case to execute, while a
series of if-else statements requires a linear search
through each condition until a match is found.
7

While Loop
while (condition) {
./ loop code
}
Do-while Loop
do {
./ loop code
} while (condition)
for(Initialization; condition; incrdecr) {
./ loop body
}
For Loop
For-in Loop
List<int> myList = [1,2 ,1, 1, 4];
for(var num in myList){
print("item: $num");
}
List<int> myList = [3,3 ,3, 4];
myList.forEach((element) {
print("item: $element");
});
ForEach Loop
Noted:
forEach is that it is often faster and more efﬁcient than
using a traditional for loop, especially for large collections.
This is because forEach uses an internal iterator that is
optimized for performance, while a traditional for loop
with an index variable may be slower due to the overhead
of incrementing and checking the index variable on each
iteration.
8

V. Function 󰥲
In programming, a function is a block of code that performs a speciﬁc task or set of tasks.
Functions can be thought of as small, self-contained units of code that can be reused
throughout a program.
9

V. Function 󰥲
int sum(int a, int b) .> a + b;
void main() {
int result = sum(5, 7);
}
Take parameters, Return values
void printMessage(String message) {
print(message);
}
void main() {
printMessage("Hello, world!");
}
Take parameters, No return values
No parameters, Return values
import 'dart:math';
int getRandomNumber() {
final random = Random();
return random.nextInt(10) + 1;
}
void main() {
int randomNum = getRandomNumber();
}
No parameters, No return values
void printList(List<int> numbers) {
for (final number in numbers) {
print(number);
}
}
void main() {
final List<int> numbers = [1, 2, 3, 4, 5];
printList(numbers);
}
10

VI. Nullability - Null Safety 📭
Null Safety in simple words means a variable cannot contain a ‘null’ value unless you
initialized with null to that variable. With null safety, all the runtime null-dereference
errors will now be shown in compile time.
final String msg1 = null; Error Null can’t be assigned to a variable
final String? msg2 = null; No error
11

VI. Nullability - Null Safety 📭
void crushMessage(String msg) {
print("MESSAGE: $msg");
}
void main() {
final String? name = "Hey, I'm a string!";
crushMessage(name); Error Null can’t be assigned to a variable
}
void crushMessage(String msg) {
print("MESSAGE: $msg");
}
void main() {
final String? name = "Hey, I'm a string!";
crushMessage(name!);
}
Bug
Solution
12

VI. Enumeration 🥇🥈🥉
In Dart, enum is a special data type that represents a group of related constants. An enum
declaration consists of a list of named constant values, called enum members.
Window MacOS Linux
13

VI. Enumeration 🥇🥈🥉
enum CustomerType {
regular,
premium,
vip
}
void main() {
CustomerType customerType = CustomerType.premium;
switch (customerType) {
case CustomerType.regular:
print('This is a regular customer.');
break;
case CustomerType.premium:
print('This is a premium customer.');
break;
case CustomerType.vip:
print('This is a VIP customer.');
break;
}
}
14

V. CLASSES 󰥍
In Dart, a class is a blueprint for creating objects that have similar characteristics and behavior.
It deﬁnes a set of attributes (also known as properties or instance variables) and methods that
can be used to manipulate those attributes.
15

IV. CLASSES 󰥍
enum Gender{Male, Female}
class Person {
final String name;
final int age;
final Gender gender;
final String? occupation;
./ constructor
Person({
required this.name,
required this.age,
required this.gender,
this.occupation,
});
./Method or Behavior
void walk(){}
void speak(){}
void eat(){}
}
void main() {
Person phanith = Person(name: "Phanith", age: 20, gender: Gender.Male, occupation: "Student");
}
Property
Constructor
Method
16

VII. Object-Oriented Programming 🔥
Dart is an object-oriented programming language, and it supports all the concepts of
object-oriented programming such as classes, object, inheritance, mixin, and abstract classes. As
the name suggests, it focuses on the object and objects are the real-life entities. The
Object-oriented programming approach is used to implement the concept like polymorphism,
data-hiding, etc. The main goal of oops is to reduce programming complexity and do several tasks
simultaneously
17

Encapsulation
Encapsulation is one of the important concepts of object-oriented programming. Before
learning about dart encapsulation, you should have a basic understanding of the class and object
in dart. Encapsulation means hiding data within a library, preventing it from outside factors. It
helps you control your program and prevent it from becoming too complicated
18

Encapsulation
class Student {
String _name;
int _age;
String _address;
String _phone;
Student(this._name, this._age, this._address, this._phone);
./ Getters
String get name .> _name;
int get age .> _age;
String get address .> _address;
String get phone .> _phone;
./ Setters
set name(String name) .> this._name = name;
set age(int age) .> _age = age;
set address(String address) .> _address = address;
set phone(String phone) .> _phone = phone;
@override
String toString() {
return 'Student: $_name, $_age, $_address, $_phone';
}
}
void main() {
Student student = Student('John', 20, '123 Main St', '555-555-5555');
print(student.toString());
}
19

Inheritance
Inheritance is a fundamental concept in object-oriented programming (OOP) that allows a new
class, called the subclass or derived class, to be based on an existing class, called the base class
or superclass. The subclass inherits properties and methods from the base class, and can also
add new properties and methods or modify the behavior of the inherited ones
20

Inheritance
class Animal {
void eat() {
print('The animal is eating');
}
}
class Dog extends Animal {
void bark() {
print('The dog is barking');
}
}
void main() {
Dog myDog = Dog();
myDog.eat();
myDog.bark();
}
21

Polymorphism
Polymorphism is a concept in object-oriented programming that allows objects of different
classes to be treated as if they were of the same type. In other words, it is the ability of an object
to take on many forms.
22

Polymorphism
class Animal {
void makeSound() {
print('The animal makes a sound');
}
}
class Dog extends Animal {
void makeSound() {
print('The dog barks');
}
}
class Cat extends Animal {
void makeSound() {
print('The cat meows');
}
}
void main() {
Animal animal = new Animal();
Animal dog = new Dog();
Animal cat = new Cat();
animal.makeSound();
dog.makeSound();
cat.makeSound();
}
23

Abstract
In programming, the term "abstract" refers to the concept of deﬁning common interface or
behavior without implementing it in detail. In object-oriented programming, an abstract class is
a class that cannot be instantiated directly, but can be used as a base class for other classes.
24

Abstract
abstract class Shape {
double area();
}
class Circle extends Shape {
double radius;
Circle(this.radius);
double area() {
return 3.14 * radius * radius;
}
}
class Rectangle extends Shape {
double width, height;
Rectangle(this.width, this.height);
double area() {
return width * height;
}
}
void main() {
Circle circle = Circle(5);
Rectangle rectangle = Rectangle(5, 10);
print(circle.area());
print(rectangle.area());
} 25

Interface
In programming, an interface is a speciﬁcation of a set of methods and properties that a class
must implement. An interface does not provide any implementation details, but rather deﬁnes a
contract or agreement between different classes that share a common set of behaviors.
26

Interface
class CountryRule {
void noGun() {
print('No gun');
}
}
class SchoolRule {
void noLongHair() {
print('No long hair');
}
}
class Student implements CountryRule, SchoolRule {
@override
void noGun() {
print('No gun');
}
@override
void noLongHair() {
print('No long hair');
}
}
void main() {
Student student = Student();
student.noGun();
student.noLongHair();
}
27

I. Asynchronous
Asynchronous programming is a programming paradigm that allows tasks to be executed
concurrently and independently of each other, without having to wait for each task to complete
before moving on to the next one. In other words, it enables a program to perform multiple
operations at the same time, which can greatly improve its performance and responsiveness.
28

VIII. Asynchronous
Future<void> printNumbers() async {
print('Starting to print numbers...');
./ wait for 1 second before printing each number
for (int i = 1; i .= 5; i.+) {
await Future.delayed(Duration(seconds: 1));
print(i);
}
print('Finished printing numbers.');
}
void main() {
printNumbers();
print('Continuing to execute other tasks...');
}
29

Practice
Exercise 01: Write a program to sum the following series:
Exercise 02: Accept 10 integers from the user to store them in an array, and display the average of the positive and negative
numbers.
Exercise 03: Write function convert decimal to binary.
Exercise 04: (Simulation firing a gun) You progress to the third game of the Squid Game. For this game, six players will play
together. Five bullets are put into a gun's round barrel which can hold up to six bullets.
A staff from the game will start pointing the gun at the first player and firing the gun. If no bullet is fired, the player survives,
otherwise, the player gets shot and die. The staff will do the same to all players one by one. Note that the staff will roll the barrel
before each shooting. Which turn (1st to 6th) would you choose to increase your chance of survival? Write a program to
simulate this gun shooting game one thousand rounds, and display the number of each player getting shot based on the turn
they take to get shot.
30

Basic Dart Programming Language 2023.pdf

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