Algorithm interview questions and answers: – How does selection sort algorithm works?

Selection sort is the most simples sorting algorithm.  It finds the lowest value from the collection and moves it to the left. This is repeated until the complete collection is sorted.

Below is a pictorial representation of how selection sort works. We have simple collection down below which has 5, 7, 1, and 0 values.

Step 1:- Find the smallest value from the collection. In the current collection the smallest value is “0”. Move this smallest value to the left hand side.

Step 2 :- Iterate again to find the next smallest value. The next smallest value is “1”. Move this value to the left hand side before the first smallest value.

In this manner continue with all elements in a collection and your list is sorted.


Below is a simple c# code for selection algorithm.

// array of integers to hold values

  private static int[] a = new int[4]{2,8,0,3};

static void Main(string[] args)



foreach (int temp in a)






public static void Sort()


int i, j;

int min, temp;

for (i = 0; i < a.Count() – 1; i++) // Loop through each element


min = i; // Assume that he is the smallest

for (j = i + 1; j < a.Count(); j++) // Loop through the remaining element


if (a[j] < a[min]) // If the current value smaller than the min


min = j; // Swap the values



temp = a[i]; // Store the current value in temp variuable

a[i] = a[min]; // Swap the minimum  value to the current position

a[min] = temp; // Swap the current value to the minimum value position



Also read inserted algorithm interview questions and answers  from

Also read Bubble sort algorithm interview questions and answers from

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This question is taken from the book c# interview question book written by Shivprasad koirala. You can buy the book from these shops à


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