300+ TOP Dart Programming Interview Questions and Answers

Dart Programming Interview Questions for freshers experienced :-

1. What is Dart?
Dart is an application programming language. It is used to build web, server and mobile applications.

2. Who is the developer of Dart?
Google is the developer of Dart.

3. How to create a simple program?
The following code for simple program:

main() {
print(“Hello World!”);
}

4. What are the ways to execute Dart Program?
There are two ways to execute Dart program:

• Via the terminal.
• Via the WebStrom IDE.

5. Is Dirt is case sensitive programming language?
Yes, Dirt is case sensitive programming language.

6. What are the data types in Dart language?
There are following data types in Dart language.

1. Numbers
2. Strings
3. Booleans
4. Lists
5. Maps

7. What is type-checking in Dart?
In Dart, type-checking is used to check that a variable hold only specific to a data type.

—————————————————————–
String name = ‘Smith’;
int num = 10;

—————————————————————–
void main() {
String name = 1; // variable Not Match
}

8. What are various string functions in Dart?
There are given various string functions:

• String Methods Description
• toLowerCase() It converts all string characters in to lower case.
• toUpperCase() It converts all string characters in this to upper case.
• trim() It returns the string without any whitespace.
• compareTo() It compares this object to another.

9. What are the types of list in Dirt?
There are two types of list in Dirt that are given below:

• Fixed Length List : (length fixed)
• Growable List: (Length can change at runtime.

10. What is the syntax for declare the map using a Map Constructor?
Map declaration syntax is:

var identifier = new Map()

11. What is rune in Dart?
In Dart, rune is an integer representing Unicode code point.

12. Does Dart has a syntax for declaring interfaces?
No, Dart has not syntax for declaring interface.

13. What is Lambda Function?
A Lambda function is a concise mechanism to represent functions. These functions are known as Arrow functions.

Example:

void main() {
printMsg();
print(test());
}
printMsg()=>
print(“hello”);
int test()=>123;
// returning function

14. What is the use of this keyword in Dart?
In Dart, this keyword refers to the current instance of the class.

void main() {
Car c1 = new Car(‘E1001’);
}
class Car {
String engine;
Car(String engine) {
this.engine = engine;
print(“The engine is : “);
}
}

15. What are Getters and Setters?
Getters and Setters allow the program to initialize and retrieve the value of class fields. It is also known as accessors and mutators.

16. What are the differences between Dart and JavaScript?
The differences between Dart and JavaScript are given below in table.

1. Feature Dart JavaScript
2. Type system Optional, dynamic Weak, dynamic
3. Classes Yes, Single inheritances Prototypical
4. Interfaces Yes, Multiple interfaces No
5. Concurrency Yes, with isolates Yes, with HTML5 web workers.

17. Which command is used to compile Dart into JavaScript?
The following command is used to compile Dart into JavaScript:

dart2js – – out=<output_file>.js <dart_script>.dart

18. Does Dart support comment?
Yes, Dart supports comment. There are two types of comment:

1. Single-line comments( // )
2. Multi-line comments ( /**/ )

19. What are the various types of operators in Dart?
In Dart, there are various types of operators:

• Arithmetic Operators
• Equality and Relational Operators
• Type test Operators
• Bitwise Operators
• Assignment Operators
• Logical Operators

20. What is the use of truncate methods?
Truncate method is used to return an integer after discarding any fractions digits.

Example:

void main() {
double n1 = 2.123;
var value = n1.truncate();
print(“The truncated value of 2.123 = “);
}

21. What is the file extension of Dart?
The file extension of Dart is .Dart.

22. What are the various methods to manipulate strings?
There are various methods to manipulate string that are given in table:

• String Methods Description
• toLowerCase() It converts all the string character into lower case.
• toUpperCase() It converts all the string character into upper case.
• trim() It returns the string without any leading and trailing whitespace.
• compareTo() It compare objects to another objects.

23. Does Dart have syntax to declare interface?
No, Class declarations are themselves interfaces in Dart.

24. What is the syntax to declare class?
The following is the syntax to declare class.

class class_name {
<fields>
<getters/setters>
<constructors>
<functions>
}

25. How to create an example of this keyword in Dart?
In Dart, the following code is used to create an example of this keyword.

void main() {
Car c1 = new Car(‘M2001’);
}
class Car {
String engine;
Car(String engine) {
this.engine = engine;
print(“The engine is : “);
}
}

26. What are Getters and Setters in Dart?
In Dart, Getters and Setters is also known as accessors and mutators. It allows the program to initialize and retrieve the values of class fields.

27. What is Method Overriding in Dart?
In Dart, Method Overriding is a technique that child class redefines a method in its parent class.

Example

void main() {
Child c = new Child();
c.m1(12);
}
class Parent {
void m1(int a){ print(“value of a “);}
}
class Child extends Parent {
@override
void m1(int b) {
print(“value of b “);
}
}

28. What is pub in Dart?
In Dart, pub is a tool for manage Dart packages.

29. What is the syntax to handle an exception?
The following syntax is used to handle an exceptions.

try {
// code that might throw an exception
}
on Exception1 {
// code for handling exception
}
catch Exception2 {
// code for handling exception
}

30. Which editor is used to enables breakpoint and step by step debugging?
WebStorm editor is used to enables breakpoint and step by step debugging.

31. What is typedef in Dart?
In Dart, A typedef (Or function types alias) helps to define pointer to execute code within memory.

Syntax:

typedef function_name(parameters)

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