program to create a class Animal and a function display in it

class Animal {
  String? name;
  int? numberOfLegs;
  int? lifeSpan;

  void display() {
    print("Animal name: $name.");
    print("Number of Legs: $numberOfLegs.");
    print("Life Span: $lifeSpan.");
  }
}

_____________________________________________________________________________________________________

program to create an object of class

 class Bicycle {
      String? color;
      int? size;
      int? currentSpeed;
    
      void changeGear(int newValue) {
        currentSpeed = newValue;
      }
    
      void display() {
        print("Color: $color");
        print("Size: $size");
        print("Current Speed: $currentSpeed");
      }
    }

    void main(){
        // Here bicycle is object of class Bicycle. 
        Bicycle bicycle = Bicycle();
        bicycle.color = "Red";
        bicycle.size = 26;
        bicycle.currentSpeed = 0;
        bicycle.changeGear(5);
        bicycle.display();
    }

_____________________________________________________________________________________________________

Another example of creating object of class

class Animal {
      String? name;
      int? numberOfLegs;
      int? lifeSpan;
    
      void display() {
        print("Animal name: $name.");
        print("Number of Legs: $numberOfLegs.");
        print("Life Span: $lifeSpan.");
      }
    }

    void main(){
        // Here animal is object of class Animal. 
        Animal animal = Animal();
        animal.name = "Lion";
        animal.numberOfLegs = 4;
        animal.lifeSpan = 10;
        animal.display();
    }

_____________________________________________________________________________________________________

Another example of creating object of class

    class Car {
      String? name;
      String? color;
      int? numberOfSeats;
    
      void start() {
        print("$name Car Started.");
      }
    }

    void main(){
        // Here car is object of class Car. 
        Car car = Car();
        car.name = "BMW";
        car.color = "Red";
        car.numberOfSeats = 4;
        car.start();

        // Here car2 is another object of class Car.
        Car car2 = Car();
        car2.name = "Audi";
        car2.color = "Black";
        car2.numberOfSeats = 4;
        car2.start();
    }

_____________________________________________________________________________________________________

Another example of creating object of class

class Animal {
  String? name;
  int? numberOfLegs;
  int? lifeSpan;

  void display() {
    print("Animal name: $name.");
    print("Number of Legs: $numberOfLegs.");
    print("Life Span: $lifeSpan.");
  }
}

void main(){
  // Here animal is object of class Animal. 
  Animal animal = Animal();
  animal.name = "Lion";
  animal.numberOfLegs = 4;
  animal.lifeSpan = 10;
  animal.display();
}

_____________________________________________________________________________________________________

Another example of creating object of class

class SimpleInterest{
  //properties of simple interest
  double? principal;
  double? rate;
  double? time;
  
  //functions of simple interest
  double interest(){
    return (principal! * rate! * time!)/100;
  }
}
void main(){
  //object of simple interest created
  SimpleInterest simpleInterest = SimpleInterest();
  
  //setting properties for simple interest
  simpleInterest.principal=1000;
  simpleInterest.rate=10;
  simpleInterest.time=2;
  
  //functions of simple interest called
  print("Simple Interest is ${simpleInterest.interest()}.");
}

_____________________________________________________________________________________________________