class Student {

String name;

int age;

int marks;

//Positional Optional Parameters

//first position is of field 'name'

//'age' & 'marks' field is optional

//'marks' field has default value 0

Student(this.name, [this.age, this.marks=0]);

@override

String toString() {

return 'Student{name: $name, age: $age, marks: $marks}';

}

}