Lesson #1

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            // 3 students
            // NO OOP!

            // Student 1
            int age1 = 21;
            string name1 = "Abbas";

            // Student 2
            int age2 = 24;
            string name2 = "Kanan";

            // Student 3
            int age3 = 20;
            string name3 = "Akif";

            // 20.000 students
            // Name
            // Age

            // Type-name instance-name
            // A3 - Student
            // A3 blank page = student1
            Student student1 = new Student();
            student1.name = "Saleh";
            student1.age = 19;

            Student student2 = new Student();
            student2.name = "Taleh";
            student2.age = 33;

            // This object is not initialized
            Student student3;

            // Default values
            // integer types => 0
            // floating-point types => 0.0
            // reference types => null
            // Reference Types [string, Student] => class

            // Array - Sequence is the same type element list.
            // 78025, 1, 2, 3, 9, -44, 0, 1001, -1000, 563 - Array
            // Array Declaration Syntax:
            // type-name[] object-name = new type-name[elementOfCount];
            float[] mySequence = new float[10];
            mySequence[5] = -44.00F;

            // Float type => 4 bytes => 32 bits
            float f1 = 64.85623F;

            // Double type => 8 bytes => 64 bits
            double d1 = 64.85623;

            // All programming languages BY DEFAULT
            // Type of Integer values => int => 4 bytes => 32 bits
            // Type of Floating values => double

            // Infinity looping
            // Initialize Condition  Iteration
            // 1. Initialize => int i = 0;
            // 2. Condition => i < 10
            // 3. Iteration => i++

            // Iteration: 2
            // Start value: 5

            // 5, 7, 9, 11, 13

            // Range: 0 ... 9
            // Odd indexes: 0, 2, 4, 6, 8 [+]
            // Even indexes: 1, 3, 5, 7, 9 [+]

            // increment => [i++] [i = i + 1] [i += 1]
            // decrement => [i--] [i = i - 1] [i -= 1]
            /*
            for (int i = 7; i < 17; i = i + 1)
            {
                // Concat => string join 0 + " => " ======>>>>>>> [0 => ]
                Console.Write(i - 7 + " => ");
                Console.WriteLine("{0:f1}", mySequence[i - 7]);
            }
            */

            /*
            // 7, 9, 11, 13, 15
            for (int i = 7; i < 17; i = i + 2)
            {
                // Concat => string join 0 + " => " ======>>>>>>> [0 => ]
                Console.Write(i - 7 + " => ");
                Console.WriteLine("{0:f1}", mySequence[i - 7]);
            }
            */

            /*
            // 8, 10, 12, 14, 16
            for (int i = 8; i < 17; i = i + 2)
            {
                // Concat => string join 0 + " => " ======>>>>>>> [0 => ]
                Console.Write(i - 7 + " => ");
                Console.WriteLine("{0:f1}", mySequence[i - 7]);
            }
            */

            // Array Declaration Syntax:
            // type-name[] object-name = new type-name[elementOfCount];
            Student[] students = new Student[3];

            // students.Length = 15; // ERROR!

            for (int i = 0; i < students.Length; i++)
            {
                students[i] = new Student();

                Console.Write("Name: ");
                students[i].name = Console.ReadLine();

                Console.Write("Age: ");
                students[i].age = int.Parse(Console.ReadLine());
            }

            Console.WriteLine("All entered student list");
            for (int i = 0; i < students.Length; i++)
            {
                Console.Write("Name #" + (i + 1) + ": ");
                Console.WriteLine(students[i].name);

                Console.Write("Age #" + (i + 1) + ": ");
                Console.WriteLine(students[i].age);
            }
        }

        private class Student
        {
            // Access modifiers
            public int age;
            public string name;
        }
    }
}