private static IEnumerable<Student> FirstNameBeforeLast(Student[] studentsArray)
{
var result = studentsArray
.Where(st => st.FirstName.CompareTo(st.LastName) < 0)
.ToArray();
return result;
}
private static IEnumerable<Student> FirstNameBeforeLast(Student[] students)
{
IEnumerable<Student> result =
from student in students
where student.FirstName.CompareTo(student.LastName) < 0
select student;
return result;
}
public static void FirstBeforeSecond(Student[] students)
{
Console.WriteLine("Students whose first name is before its lastname using LINQ:\n");
var selectedStudents =
from student in students
where ((student.FirstName).CompareTo(student.LastName) < 1)
select student;
PrintStudents(selectedStudents);
}
private static void FindStudentsWithAgeBetween18And24(Student[] studentsArray)
{
var result = studentsArray
.Where(st => ((st.Age > 18) && (st.Age < 24)))
.ToArray();
foreach (Student student in result)
{
Console.WriteLine(student.FirstName + " " + student.LastName);
}
}
static void Main()
{
Student[] students = new Student[]
{
new Student("Doncho","Minkov",24),
new Student("Niki","Kostov",23),
new Student("Pesho","Peshev",27),
new Student("Ivo","Kenov",25)
};
Student[] orderByNameStudents = SortStudentNames(students);
foreach (var student in orderByNameStudents)
{
Console.WriteLine(student.FirstName + " " + student.LastName);
}
}
static void Main()
{
Student firstStudent = new Student("Ivan", "Ivanev", 19);
Student secondStudent = new Student("Pesho", "Todorov", 22);
Student thirdStudent = new Student("Mariika", "Georgieva", 26);
Student fourthStudent = new Student("Dobromira", "Petrova", 28);
Student fifthStudent = new Student("Elena", "Krasimirova", 20);
Student sixthStudent = new Student("Dimitrichka", "Alenska", 31);
List <Student> studentCollection = new List <Student>();
studentCollection.Add(firstStudent);
studentCollection.Add(secondStudent);
studentCollection.Add(thirdStudent);
studentCollection.Add(fourthStudent);
studentCollection.Add(fifthStudent);
studentCollection.Add(sixthStudent);
//task 3
var filteredStudentst =
from stud in studentCollection
where stud.FirstName.ToLower().CompareTo(stud.LastName) == -1
select stud;
foreach (var item in filteredStudentst)
{
Console.WriteLine(item.FirstName + " ");
}//end of task 3
Console.WriteLine();
//task 4
var filterAgeRange =
from person in studentCollection
where person.Age <= 24 && person.Age >= 18
select person;
foreach (var stud in filterAgeRange)
{
Console.WriteLine(stud.FirstName + " " + stud.LastName + " |Age:" + stud.Age);
}
//end of task 4
Console.WriteLine();
//task 5
var nameDescending = studentCollection.OrderByDescending(s => s.FirstName).ThenByDescending(x => x.LastName);
foreach (var stud in nameDescending)
{
Console.WriteLine("{0}", stud.FirstName);
}
Console.WriteLine();
foreach (var stud in nameDescending)
{
Console.WriteLine("{0}", stud.LastName);
}
Console.WriteLine();
var firstLastNameDescending =
from stud in studentCollection
orderby stud.FirstName descending, stud.LastName descending
select stud;
foreach (var stud in firstLastNameDescending)
{
Console.WriteLine("{0} {1,15}", stud.FirstName, stud.LastName);
}
//end of task 5
}
private static Student[] SortStudentNames(Student[] students)
{
Student[] sortedArray = students.Where(s => string.Compare(s.FirstName, s.LastName) < 0).ToArray();
return sortedArray;
}
private static IEnumerable<Student> FindPeopleOfCertainAge(Student[] students, int startAge, int endAge)
{
IEnumerable<Student> result =
from student in students
where student.Age >= startAge && student.Age <= endAge
select student;
return result;
}
private static IEnumerable<Student> SortStudents(Student[] studentsArray)
{
var resultProblem5 = studentsArray
.OrderByDescending(st => st.FirstName)
.ThenByDescending(st => st.LastName)
.ToArray();
return resultProblem5;
}
