госы_люди_dart

void main() {
  // Create a list containing three objects of each class.
  List<People> peopleList = [
    People(name: 'Alice', age: 25),
    People(name: 'Bob', age: 32),
    People(name: 'Charlie', age: 28),
    Worker(name: 'David', age: 40, post: 'Engineer', salary: 60000),
    Worker(name: 'Eve', age: 35, post: 'Manager', salary: 75000),
    Worker(name: 'Fred', age: 29, post: 'Analyst', salary: 55000),
    Student(name: 'Grace', age: 20, marks: [85, 90, 92], subjects: ['Math', 'Science', 'History']),
    Student(name: 'Henry', age: 22, marks: [78, 82, 88], subjects: ['English', 'Art', 'Music']),
    Student(name: 'Ivy', age: 21, marks: [92, 95, 98], subjects: ['Physics', 'Chemistry', 'Biology']),
  ];

  // Print information about each person using the toString method.
  print('Information about each person:');
  for (var person in peopleList) {
    print(person);
  }

  // Print the names of those who are younger than 30 years old.
  print('\nNames of people younger than 30:');
  for (var person in peopleList) {
    if (person.age < 30) {
      print(person.name);
    }
  }

  // Calculate the average salary of all workers.
  double averageSalary = 0;
  int workerCount = 0;
  for (var person in peopleList) {
    if (person is Worker) {
      averageSalary += person.salary;
      workerCount++;
    }
  }
  averageSalary = workerCount > 0 ? averageSalary / workerCount : 0;

  // Count the number of Worker objects with a salary below the average.
  int workersBelowAverage = 0;
  for (var person in peopleList) {
    if (person is Worker && person.salary < averageSalary) {
      workersBelowAverage++;
    }
  }

  print('\nNumber of workers with salary below average: $workersBelowAverage');

  // Print information about the subjects of each Student.
  print('\nSubjects of each student:');
  for (var person in peopleList) {
    if (person is Student) {
      print('${person.name}: ${person.subjects}');
    }
  }
}

class People {
  final String name;
  final int age;

  People({required this.name, required this.age});

  @override
  String toString() => 'Name: $name, Age: $age';
}

final class Worker extends People {
  final String post;
  final int salary;

  Worker({
    required super.name,
    required super.age,
    required this.post,
    required this.salary,
  });

  @override
  String toString() => 'Name: $name, Age: $age, Post: $post, Salary: $salary';
}

final class Student extends People {
  final List<int> marks;
  final List<String> subjects;

  Student({
    required super.name,
    required super.age,
    required this.marks,
    required this.subjects,
  });

  @override
  String toString() => 'Name: $name, Age: $age, Marks: $marks, Subjects: $subjects';
}