IntroProgrammingC#ExcercisesPartTime

// Exercises
// I. first day
// 1. Hello World
using System.Security.Cryptography.X509Certificates;

Greet("Ilkay");

// 2. Variables, Primitive data Types Literals
Console.WriteLine("Test");
int a = 7;
int b = 3;
int speedOfLight = 0xe3; //300000;
Console.WriteLine((float)a/b);

// 3. Operators
Console.WriteLine(a*b > b*b*a || b + a < a*b);

// 4. Formatted output/ Reading from console
Console.WriteLine("{0,10:C2}", b);
Console.Write("Please, enter your age: ");
string age = Console.ReadLine();
int ageDigit = int.Parse(age);
Console.WriteLine("In 10 years you will be {0}", ageDigit + 10);

// Console.Write("Please, tell me how much money do you have: ");

// 5. Conditional Logic
//Console.Write("Please enter your age: ");
//string aaa = Console.ReadLine();
//int age1 = int.Parse(Console.ReadLine());

////if (age1 >= 0 && age1 <= 3)
////{
////    Console.WriteLine("You are a baby");
////}

//if (age1 >= 0 && age1 <=3)
//{
//    Console.WriteLine("You are a baby");
//}
//else if (age1 >= 3 && age1 <= 13)
//{
//    Console.WriteLine("You are a kid");
//}
//else if (age1 > 13 && age1 <= 18)
//{
//    Console.WriteLine("You are teenager!");
//}
//else
//{
//    Console.WriteLine("You are an aduld");
//}

//Console.Write("Enter the first letter of your name: ");
//char firstLetter = char.Parse(Console.ReadLine());

//switch (firstLetter)
//{
//    case 'S':
//        Console.WriteLine("You are a lucki man");
//        break;
//    case 'D':
//        Console.WriteLine("You are a great man");
//        break;
//    default:
//        Console.WriteLine("I don't know what to say");
//        break;
//}

// 6. Loops
for (int i = 0; i < 10; i++)
{
    Console.WriteLine(i);
}

// II Second day of Excercises
//7. Arrays
// Declare an array of 10 Ints assign values and print them on the console
string[] namesOfStudents = new string[] {
    "Yaren",
    "Darina",
    "Aishe",
    "Suzana",
    "Momchil",
    "Ivan...14",
    "Stanislava",
    "Ilker",
    "Ilkay",
    "Dean",
    "Nikola"
};

Console.WriteLine("Hello Deny!");

int[] numbers = new int[10];
numbers[0] = 10;
numbers[1] = 12;

foreach (var n in numbers)
{
    Console.WriteLine(n);
}
Greet("Stanislava");
int number;
do
{
    Console.Write("Please enter a number between 1 - 5: ");
    number = int.Parse(Console.ReadLine());

} while (number < 1 || number > 5);

// 8. Number systems
Console.WriteLine("2093 to BIN {0}.", Convert.ToString(2093, 2));
Console.WriteLine("2093 to OCT {0}.", Convert.ToString(2093, 8));
Console.WriteLine("2093 to HEX {0}.", Convert.ToString(2093, 16));

// 9. Methods
// Declare and define a method which grrets. First without formal parameters and returned value. After that with a formal parameter
Console.WriteLine(AddNumbers(34, 54));
static void Greet(string name = "Deny")
{
    Console.WriteLine($"Hello {name}!");
}

// Declare and define a function with a returned value which adds two digits
static int AddNumbers(int a, int b)
{
    return a + b;
}

static bool IsOdd(int num)
{
    return (num % 2 == 1)? true : false;
}

// 10. Recursion
// With the help of ChatGPT create a function factorial
// factorial
// 0! = 1
// n! = (n-1)! * n
static int Factorial(int n)
{
    if (n == 0)
    {
        return 1;
    }
    else
    {
        return n * Factorial(n - 1);
    }
}


Console.WriteLine(Factorial(3));

static double FactorialIter(int n)
{
    double factorial = 1;
    for (int i = 2; i <= n; i++)
    {
        factorial *= i;
    }
    return factorial;
}

// III. Excercise
// 1. Define a function that finds the min element in array of ints


//int[] nums = {1,2,3,4,5,6,7,8,9};

//void FindLowest()
//{
//    int lowest = int.MaxValue;
//    for (int i = 0; i < nums.Length; i++)
//    {
//        int current = nums[i];
//        if (current < lowest)
//        {
//            current = lowest;
//        }
//    }
//    Console.WriteLine( lowest);
//};
//FindLowest();


// Min
static int FindMin(int[] nArray)
{
    int min = nArray[0];
    foreach (int num in nArray)
    {
        if (min > num) { min = num; }
    }
    return min;
}

// Max
static int FindMax(int[] nArray)
{
    int max = nArray[0];
    foreach (int num in nArray)
    {
        if (max < num) { max = num; }
    }
    return max;
}

// Sort
static void BubbleSortDescending(int[] arr)
{
    int temp;
    for (int i = 0; i < arr.Length - 1; i++)
    {
        for (int j = 0; j < arr.Length - i - 1; j++)
        {
            if (arr[j] < arr[j + 1]) // For ascending order, use '>'
            {
                // Swap the elements
                temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
}

// Filter
static int[] FilterOddNumbers(int[] arr)
{
    int count = 0;
    for (int i = 0; i < arr.Length; i++)
    {
        if (arr[i] % 2 != 0)
        {
            count++;
        }
    }

    int[] result = new int[count];
    int index = 0;
    for (int i = 0; i < arr.Length; i++)
    {
        if (arr[i] % 2 != 0)
        {
            result[index] = arr[i];
            index++;
        }
    }

    return result;
}


int[] nums = { 23, 29, 354, 432, 765, 89, 90, 87, 9, 10 };
Console.WriteLine("Find Min = {0}", FindMin(nums));
Console.WriteLine("Find Min = {0}", FindMax(nums));


// int[] oddNums = nums.Where(n => n % 2 != 0).ToArray();
int[] oddNums = FilterOddNumbers(nums);
foreach (var num in oddNums)
{
    Console.WriteLine(num);
}

BubbleSortDescending(nums);

// Print the sorted array
foreach (var num in nums)
{
    Console.WriteLine(num);
}