C# Fundamentals: Development for Absolute Beginners - Dissecting the First C# Program You Created - 03

Dissecting the First C# Program You Created - 03

Enjoy!

C# 17 - Bubble Sort

Implementing a sort using insertion sort algorithm.

1. Create a new console project.
2. Edit the Program.cs inside static void Main(string[] args) file as shown below.

static void Main(string[] args)

{

     int[] array = { 2, 3, 1, 9, 4, 7, 5, 8, 6, 10, 20, 12, 18, 11, 15, 16 };

          Console.Write("Before sort: ");

          PrintArray(array);

          Console.WriteLine();

          BubbleSort(array);

          Console.Write("After sort: ");

          PrintArray(array);

          Console.ReadLine();

}




private static void BubbleSort(int[] array)

{

     int temp;

     for (int i = array.Length; i >= 0 ; i--)

     {                

          for (int x = 0; x < array.Length - 1; x++)

          {

               if (array[x] > array[x + 1])

               {

                    temp = array[x];

                    array[x] = array[x + 1];

                    array[x + 1] = temp;

                }

           }

       }

}




private static void PrintArray(int[] array)

{

     for (int i = 0; i < array.Length; i++)

     {

          Console.Write(array[i] + " ");

     }

}


3. Press F5 to run and see the results.

4. Enjoy!

References:
http://www.sorting-algorithms.com/bubble-sort
http://en.wikipedia.org/wiki/Bubble_sort
http://www.algolist.net/Algorithms/Sorting/Bubble_sort

C# 16 - Insertion Sort

Implementing a sort using insertion sort algorithm.

1. Create a new console project.
2. Edit the Program.cs inside static void Main(string[] args) file as shown below.



static void Main(string[] args)
{           
     int[] array = { 2, 3, 1, 9, 4, 7 };
     Console.Write("Before sort: ");
     PrintArray(array);
     Console.WriteLine();
     InsertionSort(array);
     Console.Write("After sort: ");
     PrintArray(array);
     Console.ReadLine();
}


private static void InsertionSort(int[] array)
{
     /*
       for i = 2:n,
            for (k = i; k > 1 and a[k] < a[k-1]; k--) 
                 swap a[k,k-1]
                 → invariant: a[1..i] is sorted
            end
     */
     for (int i = 0; i < array.Length; i++)
     {
          for (int x = i; x < 0; x--)
          {
               if (array[x] < array[x - 1])
               {
                    int temp = array[x - 1];
                    array[x - 1] = array[x];
                    array[x] = temp;
               }
           }
      }
}


private static void PrintArray(int[] array)
{
       for (int i = 0; i < array.Length; i++)
       {
            Console.Write(array[i] + " ");
       }
}


3. Press F5 to run and see the results.

4. Thank you.

References:
http://en.wikipedia.org/wiki/Insertion_sort
http://www.sorting-algorithms.com/insertion-sort

C# 15 - Selection sort

Implementing a sort using selection sort algorithm.

1. Create a new console project.
2. Edit the Program.cs inside static void Main(string[] args) file as shown below.

static void Main(string[] args)
{
    int[] array = { 3, 2, 1, 4, 8 };
    Console.Write("Before sort: ");
    PrintArray(array);
    Console.WriteLine();
    SelectionSort(array);
    Console.Write("After sort : ");
    PrintArray(array);
    Console.WriteLine();

    Console.ReadLine();
}

private static void SelectionSort(int[] sortArray)
{
    int smallest = 0;
    int smallestIndex = 0;

     /* advance the position through the entire array */
     /*   (could do i < n-1 because single element is also min element) */
     for (int i = 0; i < sortArray.Length; i++)
     {
          smallest = sortArray[i];//the smallest value is at index 0
          smallestIndex = i;//store the index of the smallest value

           //find the index of the smallest value
                for (int x = i + 1; x < sortArray.Length; x++)
                {
                    if (sortArray[x] < sortArray[i])
                        smallestIndex = x;
                }

                //swap/exchange the smallest value found with last index
                sortArray[i] = sortArray[smallestIndex];
                sortArray[smallestIndex] = smallest;
            }
        }


private static void PrintArray(int[] array)
{
     for (int i = 0; i < array.Length; i++)
     {
          Console.Write(array[i] + " ");
     }
}


3. Press F5 to run and see the results.

4. Thank you.

Reference(s):
http://en.wikipedia.org/wiki/Selection_sort
http://www.sorting-algorithms.com/selection-sort