hello.dart

void main(){
  print("Hello World");
  Student s = new Student(23,"Sanjib Narzary","G1234");
  print(s.roll);
}

class Student{
  int age;
  String name;
  String rollNumber;
  
  Student(int age, String name, String rollNumber){
    this.age = age;
    this.name = name;
    this.rollNumber = rollNumber;
  }
  
  String get roll{
    return rollNumber;
  }
}