Constructors in Dart

class Student {
  String id;
  String name;
  int age;
  double score;

  Student() {
    print("Default Constructor");
  }

  Student.fromId(String id) {
    this.id = id;
  }

  Student.fromIdAndName(String id, String name) {
    this.id = id;
    this.name = name;
  }

  Student.full(String id, String name, int age, double score) {
    this.id = id;
    this.name = name;
    this.age = age;
    this.score = score;
  }
}

void main() {
  var student1 = new Student();

  var student2 = new Student.fromId("st01");
  print("Student 2 Info");
  print("id: ${student2.id}");

  var student3 = new Student.full("st02", "name 2", 22, 6.7);
  print("Student 3 Info");
  print("id: ${student3.id}");
  print("name: ${student3.name}");
  print("age: ${student3.age}");
  print("score: ${student3.score}");
}

Output

Default Constructor

Student 2 Info
id: st01

Student 3 Info
id: st02
name: name 2
age: 22
score: 6.7