main.dart

void main() {

  // ==================BASIC USAGE 1.
  
  String singleQ = 'Single quotes';
  String doubleQ ="Double quotes";
  String doubleQtInSingQt = 'Double quotes in "single" quotes';
  String singleQtInDblQt = "Single quotes in 'double' quotes";
  String multilineOne='''A
  multiline
  string''';
  String multiLine2 ="""Another
  multiline
  string""";
  
  
  // ==================BASIC USAGE 2.
  String name = "Abdullah";
  String greeting = "Hello,";
  String message = 'Dart is fun!';
  String? nullableString;
  nullableString = "I can be null.";
  var dynamicString = "I'm dynamic.";

  
  
  // ==================STRING INTERPOLATION
  String fruit = "apple";
  int count = 3; 
  String fruitSentence = 'I have $count ${fruit}s.';
  
  
  // ==================STRING CONCATENATION
  String fullName = name + " Opadeji";
  String combinedMessage = greeting + " " + message;
  String interpolatedMessage = '$greeting $name, $message';
  
  
  
  // ==================STRING PROPERTIES
  String text = "Dart is versatile.";
  
  // 1. length → int (Returns the length of the string)
  int stringLength = text.length;
  
  // 2. isEmpty → bool (Returns true if the string is empty)
  bool isEmpty = text.isEmpty;

  // 3. isNotEmpty → bool (Returns true if the string is not empty)
  bool isNotEmpty = text.isNotEmpty;
  
  // 4. runtimeType → Type (A representation of the runtime type of the object)
  Type runtimeType = text.runtimeType;
  
  
  // ==================STRING METHODS
  String sentence = "Dart programming is easy.";
  
  // 1. toUpperCase() → String (Converts the string to uppercase)
  String upperCaseSentence = sentence.toUpperCase();

  // 2. toLowerCase() → String (Converts the string to lowercase)
  String lowerCaseSentence = sentence.toLowerCase();

  // 3. contains() → bool (Checks if the string contains a substring)
  bool containsWord = sentence.contains("programming");

  // 4. substring() → String (Extracts a portion of the string)
  String extracted = sentence.substring(5, 16);
  // 5. split() → List<String> (Splits the string into a list of substrings)
  List<String> words = sentence.split(" "); // "Hello"
}