Bubble sort in C#

Question

How can I make this better?

public int BubbleSortNonEfficient(int[] arr) {
 int temp = 0;
 int LoopCount = 0;
 for(int write = 0; write < arr.Length; write++) {
 for(int sort = 0; sort < arr.Length - 1; sort++) {
 LoopCount++;
 if(arr[sort] > arr[sort + 1]) {
 temp = arr[sort + 1];
 arr[sort + 1] = arr[sort];
 arr[sort] = temp;
 }
 }
 }
 return LoopCount;
 }

Answer 1

Your implementation will run in quadratic time in all cases. You can optimize here a bit:

public static int BubbleSort(int[] arr) {
 int loopCount = 0;
 for (int i = 1; i < arr.Length; ++i) {
 bool swapped = false;
 for (int j = 0; j < arr.Length - i; ++j) {
 loopCount++;
 if (arr[j] > arr[j + 1]) {
 swapped = true;
 int temp = arr [j];
 arr [j] = arr[j + 1];
 arr [j + 1] = temp;
 }
 }
 if (!swapped) {
 break;
 }
 }
 return loopCount;
}

The above alternative will run faster whenever the input array is "presorted," i.e., exhibits a lot of order.

Declaring the sort as static will allow the user to use your sort without actually instantiating the class it belongs to.

Last but not least: you can declare temp in the body of the inner loop, since it affects nothing.

• Fire the Bullet: thanks but I want to count so I can see wich ones are better
• coderodde: @Moder Answer edited.