Data Type

void main()

{

 int age=23;

 double height=5.7;

 print('Height:$height, Age: $age');

}

void main()

{

 double a=-123123123.00;

 double b=10.55465132465451324688465415;

 double c=123123123.123123;

 print('a=$a');

 print('b=$b');

 print('c=$c');

}

WADP to print the following string in a specific format Sample of given String  

Output: 

Twinkle, twinkle, little star,

              How I wonder what you are! 

                      Up above the world so high,                          

                                       Like a diamond in the sky. 

Twinkle, twinkle,                         little star, 

            How I wonder what you            are? 

Code:

main() {

 var value =  '''

 Twinkle, twinkle, little star,

 \t   How I wonder what you are!

 \t\t      Up above the world so high,

 \t\t            Like a diamond in the sky.

 Twinkle, twinkle, little star,

 \t     How I wonder what you      are?

 ''';

 print(value);

}

WADP  to print the following here document. Sample string : a string that you "don't" have to escape This is a ....... multi-line heredoc string --------> example
Code -
main() {

 var output = '''

 a string that you \"don\'t\" have to escape

 this

 is a ....... multi-line

 heredoc string --------> example

 ''';

 print(output);

}

Working with Strings

void main() {

 String name = 'John Doe';

 print('Name: $name');

 // Concatenation

 String greeting = 'Hello, ' + name;

 print('Greeting: $greeting');

 // Interpolation

 String interpolatedGreeting = 'Hello, $name';

 print('Interpolated Greeting: $interpolatedGreeting');

 // Length

 int length = name.length;

 print('Length: $length');

 // Upper case

 String upperCase = name.toUpperCase();

 print('Upper Case: $upperCase');

 // Lower case

 String lowerCase = name.toLowerCase();

 print('Lower Case: $lowerCase');

}

void main()

{

 bool isActive=true;

 bool isCompleted=false;

 print('is Active= $isActive, is Completed=$isCompleted');

}

void main()

{

 bool a=true;

 bool b=false;

 print('True:$a');

 print('False:$b');

}

void main( ){

 var heart_symbol = '\u2665';

 var laugh_symbol = '\u{1f600}';

 print(heart_symbol);

 print(laugh_symbol);

}

void main()

{

 String s='a';

 print(s.runes);

}

Here are 20 Dart programs showcasing various data types: Numeric, String, Boolean, Map, Set, List, and Runes. Each program demonstrates practical usage and manipulation.

1. Numeric Data Types (int and double)

void main() {

 int a = 10;

 double b = 3.14;

 print('Sum: ${a + b}');

 print('Multiplication: ${a * b}');

}

2. String Concatenation

void main() {

 String firstName = 'Sandeep';

 String lastName = 'Kumar';

 print('Full Name: $firstName $lastName');

}

3. Boolean Operations

void main() {

 bool isSunny = true;

 bool isWeekend = false;

 print('Can I go out? ${isSunny && isWeekend}');

}

4. List Creation and Access

void main() {

 List<int> numbers = [1, 2, 3, 4, 5];

 print('First number: ${numbers[0]}');

 print('All numbers: $numbers');

}

5. Map Creation and Access

void main() {

 Map<String, int> age = {'Alice': 25, 'Bob': 30};

 print('Alice\'s age: ${age['Alice']}');

}

6. Set for Unique Elements

void main() {

 Set<int> uniqueNumbers = {1, 2, 2, 3};

 print('Unique Numbers: $uniqueNumbers');

}

7. Runes (Unicode Representation)

void main() {

 Runes emoji = Runes('\u{1F600}');

 print(String.fromCharCodes(emoji)); // 😀

}

8. Numeric Operations

void main() {

 int x = 5;

 int y = 2;

 print('Division: ${x / y}');

 print('Modulus: ${x % y}');

}

9. String Interpolation

void main() {

 String language = 'Dart';

 print('I am learning $language programming!');

}

10. Boolean Negation

void main() {

 bool isRainy = true;

 print('Can I go out? ${!isRainy}');

}

11. List Manipulation

void main() {

 List<int> nums = [1, 2, 3];

 nums.add(4);

 print(nums);

}

12. Map Keys and Values

void main() {

 Map<String, String> capitals = {'India': 'Delhi', 'USA': 'Washington'};

 print('Keys: ${capitals.keys}');

 print('Values: ${capitals.values}');

}

13. Set Operations

void main() {

 Set<int> a = {1, 2, 3};

 Set<int> b = {3, 4, 5};

 print('Union: ${a.union(b)}');

 print('Intersection: ${a.intersection(b)}');

}

14. Numeric Casting

void main() {

 double num = 5.7;

 print('As int: ${num.toInt()}');

}

15. String Methods

void main() {

 String text = 'Hello World';

 print('Length: ${text.length}');

 print('Uppercase: ${text.toUpperCase()}');

}

16. Boolean in Conditional

void main() {

 bool isAvailable = true;

 if (isAvailable) {

   print('The item is available!');

 } else {

   print('The item is not available!');

 }

}

17. List with Mixed Data Types

void main() {

 List<dynamic> mixedList = [1, 'Hello', true];

 print('Mixed List: $mixedList');

}

18. Map Nested Structure

void main() {

 Map<String, Map<String, int>> nestedMap = {

   'Class1': {'Alice': 90, 'Bob': 85},

   'Class2': {'John': 80, 'Doe': 95}

 };

 print('Class1 Marks: ${nestedMap['Class1']}');

}

19. Set Contains Check

void main() {

 Set<int> nums = {1, 2, 3};

 print('Contains 2: ${nums.contains(2)}');

}

20. Runes with String

void main() {

 String heart = '\u2764';

 String smiley = '\u{1F642}';

 print('I $heart Dart $smiley');

}

void main()

{

 Set<String> vowels={'A','E','I','O','U'};

 print('vowels');

}

Ex=

void main()

{

 // var st=<int>{1,2,2,3.3,"a"};

 // var st=<var>{1,2,2,3.3,"b"};

 var st=<dynamic>{1,2,2,3.3,"b"};

 var st1=<double>{1,2.2,3,3};

var st2=<bool>{true,false};

 print(st);

 print(st1);

 print(st2);

}

Ex=

void main()

{

 var x = 23;

 var y = 23;

 var z = 45;

 var list = <int>[];

 list.add(x);

 list.add(y);

 list.add(z);

 list.add(x);

 print(list);

 var set = <int>{};

 set.add(x);

 set.add(y);

 set.add(z);

 set.add(x);

 print(set);

}

Prog.1:

void main()

{

 List<String> fruits=['Apple','Banana','cherry'];

 for(String fruit in fruits)

   {

     print(fruit);

   }

}

Program 2: Working with Lists

void main() {

 List<String> fruits = ['apple', 'banana', 'cherry'];

 print('Fruits: $fruits');

 // Add an element

 fruits.add('date');

 print('Fruits after add: $fruits');

 // Remove an element

 fruits.remove('banana');

 print('Fruits after remove: $fruits');

 // Get an element by index

 String firstFruit = fruits[0];

 print('First Fruit: $firstFruit');

 // Check if an element exists

 bool hasCherry = fruits.contains('cherry');

 print('Has Cherry: $hasCherry');

}

void main()

{

 var heart = '\u2665'; // Unicode for heart symbol

 print('Heart symbol: $heart');

}

ex=

void main( ){

 var heart_symbol = '\u2665';

 var laugh_symbol = '\u{1f600}';

 print(heart_symbol);

 print(laugh_symbol);

}

ex=

void main()

{

 String s='a';

 print(s.runes);

}

void main() {

 Map<int, String> student = {1: 'sandeep', 2: 'pradeep', 3: 'pooja'};

 print(student);

}

Program 3: forEach with Maps

void main()

{

 Map<int, String> student={1:'sandeep',2:'pradeep',3:'pooja'};

 student.forEach((roll, name)

 {

   print('roll:$roll, name=$name');

 });

}

Program 3: Working with Maps

void main() {

 Map<String, int> personData = {'John': 30, 'Alice': 25};

 print('Person Data: $personData');

 // Add a new entry

 personData['Bob'] = 40;

 print('Person Data after add: $personData');

 // Update an existing entry

 personData['John'] = 31;

 print('Person Data after update: $personData');

 // Remove an entry

 personData.remove('Alice');

 print('Person Data after remove: $personData');

 // Check if a key exists

 bool hasJohn = personData.containsKey('John');

 print('Has John: $hasJohn');

}

Program 4: Working with Sets

void main() {

 Set<int> uniqueNumbers = {1, 2, 3, 3, 4};

 print('Unique Numbers: $uniqueNumbers');

 // Add an element

 uniqueNumbers.add(5);

 print('Unique Numbers after add: $uniqueNumbers');

 // Remove an element

 uniqueNumbers.remove(3);

 print('Unique Numbers after remove: $uniqueNumbers');

 // Check if an element exists

 bool hasTwo = uniqueNumbers.contains(2);

 print('Has Two: $hasTwo');

}

1. Create and Access a List

void main() {

 List<int> numbers = [10, 20, 30];

 print('First element: ${numbers[0]}');

 print('All elements: $numbers');

}

2. Add and Remove Elements from a List

void main() {

 List<String> fruits = ['Apple', 'Banana'];

 fruits.add('Orange');

 fruits.remove('Banana');

 print(fruits);

}

3. Iterating Over a List

void main() {

 List<int> numbers = [1, 2, 3];

 for (var number in numbers) {

   print(number);

 }

}

4. Check for Element in a List

void main() {

 List<String> names = ['Alice', 'Bob'];

 print(names.contains('Alice')); // true

}

5. Create and Access a Map

void main() {

 Map<String, int> scores = {'Alice': 85, 'Bob': 90};

 print('Alice\'s score: ${scores['Alice']}');

}

6. Add and Remove Keys in a Map

void main() {

 Map<String, String> capitals = {'India': 'Delhi'};

 capitals['USA'] = 'Washington';

 capitals.remove('India');

 print(capitals);

}

7. Iterating Over a Map

void main() {

 Map<String, int> data = {'A': 1, 'B': 2};

 data.forEach((key, value) {

   print('$key: $value');

 });

}

8. Nested Map Example

void main() {

 Map<String, Map<String, int>> students = {

   'Class1': {'Alice': 90, 'Bob': 80},

   'Class2': {'John': 85, 'Jane': 95},

 };

 print('Class1: ${students['Class1']}');

}

9. Create and Access a Set

void main() {

 Set<int> numbers = {1, 2, 3};

 print('Set: $numbers');

 print('Contains 2: ${numbers.contains(2)}');

}

10. Add and Remove Elements from a Set

void main() {

 Set<String> animals = {'Dog', 'Cat'};

 animals.add('Bird');

 animals.remove('Cat');

 print(animals);

}

11. Union and Intersection of Sets

void main() {

 Set<int> setA = {1, 2, 3};

 Set<int> setB = {3, 4, 5};

 print('Union: ${setA.union(setB)}');

 print('Intersection: ${setA.intersection(setB)}');

}

12. Convert a List to a Set

void main() {

 List<int> numbers = [1, 2, 2, 3];

 Set<int> uniqueNumbers = numbers.toSet();

 print(uniqueNumbers); // {1, 2, 3}

}

13. Using Runes for Unicode

void main() {

 Runes emoji = Runes('\u{1F600}');

 print(String.fromCharCodes(emoji)); // 😀

}

14. Iterating Over Runes in a String

void main() {

 String text = 'Hello 😊';

 text.runes.forEach((int rune) {

   print(String.fromCharCode(rune));

 });

}

16. Map with Default Values

void main() {

 Map<String, String> countries = {'India': 'Delhi'};

 print(countries['USA'] ?? 'Not Found'); // Output: Not Found

}

17. Remove Duplicate Elements in a List Using a Set

void main() {

 List<int> numbers = [1, 1, 2, 3, 3, 4];

 Set<int> uniqueNumbers = numbers.toSet();

 print(uniqueNumbers.toList()); // [1, 2, 3, 4]

}

18. Sort a List

void main() {

 List<int> numbers = [5, 3, 8, 1];

 numbers.sort();

 print(numbers); // [1, 3, 5, 8]

}

19. Filter Elements in a List

void main() {

 List<int> numbers = [1, 2, 3, 4, 5];

 List<int> evenNumbers = numbers.where((num) => num.isEven).toList();

 print(evenNumbers); // [2, 4]

}

20. Combining Runes and Emojis

void main() {

 Runes heart = Runes('\u2764');

 Runes smile = Runes('\u{1F604}');

 print(String.fromCharCodes(heart) + ' ' + String.fromCharCodes(smile)); // ❤️ 😄

}

WADP  to parse a string to Float or Integer.

import 'dart:io';

main() {

 var value = stdin.readLineSync()!;

 int parse_int = int.parse(value);

 double parse_double = double.parse(value);

 print("Integer: $parse_int\n Double: $parse_double");

}

void main() {

 dynamic variable = "Hello";

 print(variable);

 variable = 42; // Now it's an integer

 print(variable);

 variable = 4.2; // Now it's an FLOATING POINT

 print(variable);

}

import 'dart:io';

void main()

{

 int score=10; //number

 double height=5.9;

 print('score:=$score, height:=$height');

 String name='sandeep'; //string

 print('name:=$name');

 bool isprogrammer =false; //boolean

 print('isProgrammer: $isprogrammer');

 List<String> color =['R','G','B','1', "1"]; //list type

 print('Colour List:=$color');

 Map<int, String> St_grd={90:'sandeep', 80:'pradeep', 70:'pooja'};//map type

 print("Map grade:=$St_grd");

 Set<int> uniqueNo={1,2,3,4,5,5};//set type

print('NumberSet is:=$uniqueNo');

Runes unicode='a, bc'.runes; //unicode  type

print('Unicode:=$unicode');

Symbol sym=#mySchool; //symbol type

print('Symbol:=$sym');

}

void main() {

 String? nullableName; // This can hold a String or null

 if (nullableName == null) {

   print('Name is NULL');

 } else {

   print('Name: $nullableName');

 }

}