/*Der er brugt Metoder og  i opgaven, så shortcuts > kompleksitet*/



/*
 1. Sum of Elements in a List

· Task: Write a program that takes a list of integers
and calculates the sum of all elementsusing a for loop.

*/

void Opgave1()
{
    List<int> listeInt = new List<int>() { 1, 2, 3 };

    int værdi = 0;
    for (int i = 0; i < listeInt.Count; i++)
    {
        Console.WriteLine(listeInt[i]);
        // alternativ: værdi = værdi + listeInt[i];
        værdi += listeInt[i];
    }
    Console.WriteLine("Samlede værdi er " + værdi);
}

/*

2. Find the Maximum and Minimum Element in a List

· Task: Write a program that takes a list of integers and
finds the maximum and minimum values using a loop and if-else selection statements.

den nemme metode: {
    List<int> listeInt = new List<int>() { 1, 2, 3 };
    Console.WriteLine("Største værdi: " + listeInt.Max() + " og mindste værdi: " + listeInt.Min());
} */

void Opgave2()
{
    List<int> listeInt = new List<int>() { 11, 2, 3, 9 };
    int maxVærdi = listeInt[0];
    int minVærdi = listeInt[0];

    foreach (int i in listeInt)
    {
        if (i > maxVærdi)
        {
            maxVærdi = i;
        }

        if (i < minVærdi)
        {
            minVærdi = i;
        }
    }
    Console.WriteLine("Maksværdi er: " + maxVærdi + "\nMinværdi er: " + minVærdi);
}

/*
3. Find the Average of List Elements

· Task: Write a program that calculates the average value of elements in a list.
Use a loop to sum the elements and then divide by the count of elements.
*/

void Opgave3()
{
    int sum = 0;
    List<int> listeInt = new List<int>() { 1, 2, 3 };

    foreach (int i in listeInt)
    {
        sum += i;
    }
    // Sikrer korrekt beregning af gennemsnit (heltal til heltal division)
    Console.WriteLine("Gennemsnitsværdi er: " + (double)sum / listeInt.Count);
}

/*
4. Check if a List Contains a Specific Element

· Task: Write a program that asks the user for an integer input and checks if the
contains that element. Use a foreach loop and an if statement.

        (brugerListe.Contains(brugerInput)) */

void Opgave4()
{
    List<int> brugerListe = new List<int>() { 1, 2, 33, 4, 4, 5, 3, 3, 4, 2, 23, 42, 34234235 };

    Console.WriteLine("Skriv en liste af værdier herunder, vi tjekker om de er i listen:\n");

    int brugerInput = Convert.ToInt32(Console.ReadLine());

    foreach (int i in brugerListe)
    {
        if (brugerInput == i)
        {
            Console.WriteLine("Denne værdi er i listen: " + i);
            break;
        }
    }

}


/*
5. Copy an Array into a List

· Task: Write a program that takes a one-dimensional array and copies all elements into a list.
Use a loop to iterate through the array and add each element to the list.
*/

void Opgave5()
{
    string[] oneDimensionalArray = new string[] { "2", "3", "4", "6" };

    List<string> strings = new List<string>();

    foreach (string værdi in oneDimensionalArray)
    {
        strings.Add(værdi);
    }
    Console.WriteLine("Her er array->listen: " + string.Join(", ", strings));
}

/*
6. Count Odd and Even Numbers in an Array

· Task: Write a program that counts how many odd and even numbers are in an array.
Use a loop and selection statements (if checks for odd or even) to count the occurrences.

*/

void Opgave6()
{
    int lige = 0;
    int ulige = 0;

    int[] liste = { 1, 2, 3, 4, 5, 56, 8, 76, 5, 4, 32, 2, 4, 5, 7, 87, 65, 4, 2 };

    foreach (int i in liste)
    {
        if (i % 2 == 0)
        {
            Console.WriteLine("Tallet er lige: " + i);
            lige++;
        }
        else
        {
            Console.WriteLine("Tallet er ulige: " + i);
            ulige++;
        }
    }
    Console.WriteLine("Antal lige: " + lige + ", Antal ulige: " + ulige);
}




/*
7. Reverse the Elements of a List

· Task: Write a program that reverses the order of elements in a list using a loop.
You can either modify the list in place or create a new list to store the reversed elements.
*/
void Opgave7()
{
    List<int> ints = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    ints.Reverse();
    Console.WriteLine("Reversed liste: " + string.Join(", ", ints));
}

/*
8. Sort a List Using Selection Sort

· Task: Implement the selection sort algorithm using loops to sort a list of integers in ascending order.

*/
void Opgave8()
{
    List<int> ints = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    ints.Sort();
    Console.WriteLine("Sorteret liste: " + string.Join(", ", ints));
}

/*
9. Remove a Specific Element from a List

· Task: Write a program that asks the user for an integer input and removes all occurrences
of that element from a list using a loop and an if condition.
*/

Opgave9()
    {
    List<int> ints = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    Console.WriteLine("Skriv inputs du vil slette, gå ud af programmet med (x):\n")
    inputRemoval = Console.ReadLine();
    while (inputRemoval != "x")
    {ints.Remove(inputRemoval)}
}


/*
10. Merge Two Lists

· Task: Write a program that takes two lists and merges them into a third list.
Use loops to append elements from both lists into the new one.
*/

void Opgave10()
{
    List<int> ints1 = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    List<int> ints2 = new List<int>() { 1, 2, 9, 7, 5, 6, 7, 8, 9, 3, 2, 1, 6 };

    List<int> thirdList = new List<int>(ints1);
    thirdList.AddRange(ints2);

    Console.WriteLine("Sammensat liste: " + string.Join(", ", thirdList));
}


/*
11. Shift Elements of an Array

· Task: Write a program that shifts the elements of a one-dimensional array to the left by one position.
The first element should move to the end of the array.
*/

List<int> ints = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
foreach (int i in ints)
{
    ints[i] = ints[(ints.Length)-1];
}

/*
12. Find the Second Largest Element in a List

· Task: Write a program that finds the second largest element in a list of integers.
Avoid sorting the list directly; instead,
iterate through the list to find the two largest distinct elements.
*/

Opgave12()
{
    List<int> ints = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    ints.Sort();
    andenStørste = ints[(ints.Length) - 1]
    Console.WriteLine(andenStørste);
}
Opgave12();

/*
13. Find Duplicates in a List

· Task: Write a program that checks for duplicate elements in a list and prints them.
Use nested loops to compare each element with others and if statements to detect duplicates.
*/
void Opgave13()
{
    List<int> ints = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9, 3, 5, 7 };
    HashSet<int> set = new HashSet<int>();
    List<int> duplicates = new List<int>();

    foreach (int tal in ints)
    {
        if (!set.Add(tal))
        {
            duplicates.Add(tal);
        }
    }

    Console.WriteLine("Duplicate værdier: " + string.Join(", ", duplicates));
}


/*
14. Count Positive and Negative Numbers in a List

· Task: Write a program that counts how many positive and negative numbers are in a list.
Use a foreach loop and if-else statements to keep track of the counts.
*/

Opgave14()
{List<int> ints = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
negativeNumre = 0;
positiveNumre = 0;

foreach (int i in ints)
{
    if (i < 0)
    {
        negativeNumre++;
    }
    else
    {
        positiveNumre++;
    }
}
    Console.WriteLine($"Positive numre: {positiveNumre}, og negative numre: {negativeNumre}");
}