private static void PrintStudents(Student[] students)
{
foreach (var item in students)
{
Console.WriteLine(item);
}
}
static void Main(string[] args)
{
Student[] groups = new Student[]
{
new Student("Celine", "Dion",14),
new Student("Celine", "Youknowwho",22),
new Student("Who", "Doctor",29)
};
Console.WriteLine("The entered names are Celine Dion(age 14), Celine Youknowwho(age 22), Who Doctor(age 29)");
Console.WriteLine("Result:");
FindStudents(groups);
Console.WriteLine("Result for age:");
AgeRange(groups);
Console.WriteLine("Sorting using lambda expressions:");
var sortedLambda = groups.OrderByDescending(temp => temp.FirstName).ThenByDescending(temp => temp.LastName);
foreach (var a in sortedLambda)
{
Console.WriteLine(a.FirstName +" " + a.LastName);
}
Console.WriteLine("Sorting using LINQ:");
var sortedLINQ =
from studs in groups
orderby studs.FirstName descending, studs.LastName descending
select studs;
foreach (var stud in sortedLINQ)
{
Console.WriteLine(stud.FirstName + " " + stud.LastName);
}
}
public static IEnumerable<Student> FirstNameBeforeLast(Student[] students)
{
var result =
from student in students
where student.FirstName.CompareTo(student.LastName) < 0
select student;
return result;
}
// Task 4 "Age range"
public static Student[] FilterByAge(Student[] students)
{
var filters =
from st in students
where st.Age > 17 && st.Age < 25
select st;
return filters.ToArray();
}
// Task 3 "First before last"
public static Student[] FilterStudentsByName(Student[] students)
{
var items =
from st in students
where st.FirstName.CompareTo(st.LastName) < 0
select st;
return items.ToArray();
}
public static void FindStudents(Student[] array)
{
var group =
from stud in array
where stud.FirstName[0] < stud.LastName[0]
select stud;
foreach( var stud in group)
{
Console.WriteLine(stud.FirstName + " " + stud.LastName);
}
}
public static void AgeRange(Student[] array)
{
var group =
from stud in array
where stud.Age>=18 && stud.Age<=24
select stud;
foreach (var stud in group)
{
Console.WriteLine(stud.FirstName + " " + stud.LastName);
}
}
static void Main()
{
Student[] studentsArray = new Student[] {
new Student("Gosho", "Toshev"),
new Student("Dimitar", "Vasilev"),
new Student("Vasil", "Dimitrov"),
new Student("Jeliazko", "Momchilov")};
var FindStdUnderCondition =
from student in studentsArray
where student.FirstName.CompareTo(student.LastName) < 0
select student;
foreach (var student in FindStdUnderCondition)
{
Console.WriteLine(student.FirstName + " " + student.LastName);
}
}
static void Main(string[] args)
{
// Problem 3: Write a method that from a given array of
//students finds all students whose first name is before its last name alphabetically.
Console.WriteLine("Students whose first name is before their last alphabetically:\n");
Student[] students = new Student[] { new Student("Andrey", "Mitev"), new Student("Mile", "Andreev") };
Student[] filtered = FilterStudentsByName(students);
PrintStudents(filtered);
// Problem 4: Write a LINQ query that finds the first name and last name of all students with age between 18 and 24.
students = new Student[] {
new Student("Ivan", "Peshev", 22),
new Student("Dimitar", "Dimitrov", 65),
new Student("Ivan", "Toshev", 13),
new Student("Atanas", "Mladenov", 18),
new Student("Kaloyan", "Mladenov", 28)
};
filtered = FilterByAge(students);
Console.WriteLine("\nFiltered by age:");
PrintStudents(filtered);
// Problem 5: Using the extension methods OrderBy() and ThenBy() with
// lambda expressions sort the students by first name and last name in descending order.
Console.WriteLine("\nSorted students:");
students = students.OrderByDescending(x => x.FirstName).ThenByDescending(x => x.LastName).ToArray();
PrintStudents(students);
// Same thing done with LINQ
var sorted =
from student in students
orderby student.FirstName descending, student.LastName descending
select student;
Console.WriteLine("\nSorted with LINQ:");
PrintStudents(sorted.ToArray());
}
public static void Main()
{
Student[] students = new Student[]
{
new Student("Zornitsa", "Ivanova", 26),
new Student("Ivan", "Simeonov", 34),
new Student("Albena", "Angelova", 20),
new Student("Daniel", "Popov", 22),
new Student("Stefan", "Nikolov", 29),
new Student("Petar", "Georgiev", 28),
new Student("Maria", "Petrova", 36),
};
//Students before sorting
foreach (var student in students)
{
Console.WriteLine(student);
}
Console.WriteLine("\n3. First before last:\n");
var sortedStudents = FirstNameBeforeLast(students);
//3. First before last
foreach (var student in sortedStudents)
{
Console.WriteLine(student);
}
Console.WriteLine("\n4. Fist name + Last name, age: 18-24:\n");
//4. Age range
var ageRange =
from student in students
where student.Age >= 18 && student.Age <= 24
select student.FirstName + " " + student.LastName;
foreach (var student in ageRange)
{
Console.WriteLine(student);
}
Console.WriteLine("\n5. Order students\n");
//5. Order students
var studentInDescendingOrder = students
.OrderByDescending(st => st.FirstName)
.ThenByDescending(st => st.LastName);
foreach (var student in studentInDescendingOrder)
{
Console.WriteLine(student);
}
//Using LINQ
var studentInDescendingOrderLINQ =
from student in students
orderby student.FirstName descending, student.LastName descending
select student;
Console.WriteLine();
foreach (var student in studentInDescendingOrderLINQ)
{
Console.WriteLine(student);
}
}
static void Main()
{
var students = new Student[]
{
new Student("Ivan", "Petkov", 15),
new Student("Angel", "Georgiev", 25),
new Student("Pesho", "Atanasov", 23),
new Student("Stoqn", "Dimitrov", 19),
new Student("Angel", "Ivanov", 33),
};
//Problem 3. First before last
//Write a method that from a given array of students finds all students whose first name is before its last name alphabetically.
//Use LINQ query operators.
var filteredStudents =
from student in students
where student.FirstName.CompareTo(student.LastName) < 0
select student;
Console.WriteLine("Students whose first name is before its last name:");
foreach (var student in filteredStudents)
{
Console.WriteLine(student);
}
//Problem 4. Age range
//Write a LINQ query that finds the first name and last name of all students with age between 18 and 24.
var studentsAgeRange =
from student in students
where student.Age >= 18 && student.Age <= 24
select student;
Console.WriteLine("\nStudents with age between 18 and 24:");
foreach (var student in studentsAgeRange)
{
Console.WriteLine(student.FirstName + " " + student.LastName);
}
//Problem 5. Order students
//Using the extension methods OrderBy() and ThenBy() with lambda expressions sort the students
//by first name and last name in descending order.
//Rewrite the same with LINQ.
Console.WriteLine("\nOrdered students:");
//using extension methods
var sortedStudentsExt = students.OrderByDescending(st => st.FirstName).ThenByDescending(st => st.LastName);
Console.WriteLine("Using extension methods.");
foreach (var student in sortedStudentsExt)
{
Console.WriteLine(student);
}
//using LINQ query
var sortedStudentsLinqQuery =
from student in students
orderby student.FirstName descending, student.LastName descending
select student;
Console.WriteLine("\nUsing LINQ query.");
foreach (var student in sortedStudentsExt)
{
Console.WriteLine(student);
}
}
