import 'dart:io';
  
void main() {
  
Triangle t1= Triangle(3, 4);
  print("Triangle Area is ${t1.area()}");
  
  Rectangle r1= Rectangle(8, 6);
  print("Rectangle Area is ${r1.area()}");
  
}

class Shape{

  int width;
  int height;
  Shape(int this.width, int this.height);
  

}

class Triangle extends Shape{
  Triangle(int width, int height):super(width, height);
  
  double area() => (width*height)/2;
}
class Rectangle extends Shape{
  
    Rectangle(int width, int height):super(width, height);
  
  int area()=> width*height;
}