Dart

Question 1

Dart overview

Answer 1

• Object oriented language
• Statically Typed
• C-Style Syntax
• Multiple Runtime Env.

Question 2

Sample method

Answer 2

String myName () {
  return 'Stephen';
}

Question 3

Main method

Answer 3

void main ( ) { … }

Question 4

Variable declaration

Answer 4

var name = myName();
const value = 1000;

Question 5

Type System

Answer 5

• Every value has a type
• Every variable has a type reference
• variables type cannot change
• Dart can guess type

Question 6

Built-in Types

Answer 6

• numbers
• strings
• booleans
• lists (arrays)
• sets
• maps
• runes (Unicode char strings)
• symbols

Question 7

Number types

Answer 7

• int -2^63 to 2^63 - 1
• double IEEE 754
• both of them are subtypes of num

var y = 1;
var hex= 0xDEADBEEF;
var y = 1.1;
var exponents = 1.42e5;

double z = 1; // equalst to z=1.0

Question 8

Numbers to String and back

Answer 8

int. parse(‘1’);
double. parse(‘1.1’);
1. toString();
3. 14.toStringAsFixed(2);

Question 9

Bitwise Operators

Answer 9

«_space;» & |

Question 10

What is a String?

Answer 10

UTF-16 unit sequence

Question 11

Create Strings

Answer 11

var s1 = 'Single quotes work well for string literals.';
var s2 = "Double quotes work just as well.";
var s3 = 'It\'s easy to escape the string delimiter.';
var s4 = "It's even easier to use the other delimiter.";

Question 12

String expressions

Answer 12

• ${expression}
• If the expression is an identifier, you can skip the {}

var s = 'string interpolation';
'Dart has $s, which is very handy.'

Question 13

String equality

Answer 13

The == operator tests whether two objects are equivalent. Two strings are equivalent if they contain the same sequence of code units.

Question 14

Concat Strings

Answer 14

You can concatenate strings using adjacent string literals or the + operator:

var s1 = 'String '
    'concatenation'
    " works even over line breaks.";

Question 15

Multi-line string

Answer 15

use a triple quote with either single or double quotation marks:

var s1 = ‘’’
You can create
multi-line strings like this one.
‘’’;

Question 16

Raw String

Answer 16

You can create a “raw” string by prefixing it with r:
var s = r'In a raw string, not even \n gets special treatment.';