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× C# Examples


Bubble sort is the simplest sorting algorithm. The Bubble sort is based on the idea that every adjacent elements are compared and swapped if found in wrong order.

Example:

To understand the bubble sort, lets consider an unsorted array [1, 23, 10, -2] and discuss each step taken to sort the array in ascending order. In every pass, two adjacent elements are checked and swapped if found in wrong order.

First Pass: (1) and (23) are compared and found in correct order(ascending order in this case). After that (23) and (10) are compared, since (23>10), hence these numbers are swapped. Then (23) and (-2) are compared and swapped.

Second Pass: (1) and (10) are compared and found in correct order. Then (10) and (-2) are compared, since (10>-2), hence these numbers are swapped. After that (10) and (23) are compared and found in correct order.

Third Pass: (1) and (-2) are compared, since (1>-2), hence these numbers are swapped. After that (1,10) and (10,23) are checked and found in correct order.

Bubble Sort

Implementation of Bubble Sort

using System;

class MyProgram {
  // function for bubble sort
  static void bubblesort(int[] Array) {
  int n = Array.Length;
    int temp;
    for(int i=0; i<n; i++) {
      for(int j=0; j<n-i-1; j++) {
        if(Array[j]>Array[j+1]) {
          temp = Array[j];
          Array[j] = Array[j+1];
          Array[j+1] = temp;
        }
      }
    }
  }

  // function to print array
  static void PrintArray(int[] Array) { 
    int n = Array.Length; 
    for (int i=0; i<n; i++)  
      Console.Write(Array[i] + " "); 
    Console.Write("\n"); 
  } 

  // test the code
  static void Main(string[] args) {
    int[] MyArray = {1, 10, 23, 50, 4, 9, -4};
    Console.Write("Original Array\n");
    PrintArray(MyArray);

    bubblesort(MyArray);
    Console.Write("\nSorted Array\n");
    PrintArray(MyArray);  
  }
}

The above code will give the following output:

Original Array
1 10 23 50 4 9 -4 

Sorted Array
-4 1 4 9 10 23 50

Time Complexity:

The time complexity of bubble sort is Θ(N²) in all cases even if the whole array is sorted because the entire array need to be iterated for every element and it contains two nested loops.