Dart programming language Interview Questions & Answers

Question 1. What Is Dart?

Answer :

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

Question 2. Who Is The Developer Of Dart?

Answer :

Google is the developer of Dart.

Question 3. How To Create A Simple Program?

Answer :

The following code for simple program:

main() {   

   print("Hello World!");   

}  

Question 4. What Are The Ways To Execute Dart Program?

Answer :

There are two ways to execute Dart program:

• Via the terminal.
• Via the WebStrom IDE.

Question 5. Is Dirt Is Case Sensitive Programming Language?

Answer :

Yes, Dirt is case sensitive programming language.

Question 6. What Are The Data Types In Dart Language?

Answer :

There are following data types in Dart language:

• Numbers
• Strings
• Booleans
• Lists

Question 7. What Is Type-checking In Dart?

Answer :

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  

}  

Question 8. What Are Various String Functions In Dart?

Answer :

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.

Question 9. What Are The Types Of List In Dirt?

Answer :

There are two types of list in Dirt that are given below:

Fixed Length List : (length fixed)

Growable List: (Length can change at runtime.

Question 10. What Is The Syntax For Declare The Map Using A Map Constructor?

Answer :

Map declaration syntax is:

var identifier = new Map()  

Question 11. What Is Rune In Dart?

Answer :

In Dart, rune is an integer representing Unicode code point.

Question 12. Does Dart Has A Syntax For Declaring Interfaces?

Answer :

No, Dart has not syntax for declaring interface.

Question 13. What Is Lambda Function?

Answer :

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  

Question 14. What Is The Use Of This Keyword In Dart?

Answer :

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 : ");   

   }   

}     

Question 15. What Are Getters And Setters?

Answer :

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

Question 16. Which Command Is Used To Compile Dart Into Javascript?

Answer :

The following command is used to compile Dart into JavaScript:

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

Question 17. Does Dart Support Comment?

Answer :

Yes, Dart supports comment. There are two types of comment:

• Single-line comments( // )
• Multi-line comments ( /**/ )

Question 18. What Are The Various Types Of Operators In Dart?

Answer :

In Dart, there are various types of operators:

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

Question 19. What Is The Use Of Truncate Methods?

Answer :

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 = ");   

}   

Question 20. What Is The File Extension Of Dart?

Answer :

The file extension of Dart is .Dart.

Question 21. What Are The Various Methods To Manipulate Strings?

Answer :

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.

Question 22. Does Dart Have Syntax To Declare Interface?

Answer :

No, Class declarations are themselves interfaces in Dart.

Question 23. What Is The Syntax To Declare Class?

Answer :

The following is the syntax to declare class:

class class_name {    

   <fields>   

   <getters/setters>   

   <constructors>   

   <functions>   

}  

Question 24. How To Create An Example Of This Keyword In Dart?

Answer :

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 : ");   

   }   

}   

Question 25. What Are Getters And Setters In Dart?

Answer :

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.

Question 26. What Is Method Overriding In Dart?

Answer :

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 ");   

   }   

}  

Question 27. What Is Pub In Dart?

Answer :

In Dart, pub is a tool for manage Dart packages.

Question 28. What Is The Syntax To Handle An Exception?

Answer :

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   

}   

Question 29. Which Editor Is Used To Enables Breakpoint And Step By Step Debugging?

Answer :

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

Question 30. What Is Typedef In Dart?

Answer :

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

Syntax:

typedef function_name(parameters)