Selective sorting and bubble sorting [C language]

1、 Sorting by selection

/*
 Sorting by selection : From small to large 
 Here's how it works ： First, find the minimum in the unsorted sequence （ Big ） Elements , To the beginning of the collating sequence ,
 then , Continue to find the smallest from the remaining unsorted elements （ Big ） Elements , Then put it in the row 
 End of sequence . And so on , Until all the elements are sorted .
*/
void sel_sort_s2b(int arr[], int n)
{
	int min;
	int temp;

	for (int i = 0; i<(n - 1); i++)
	{
		min = i;
		for (int j = i + 1; j<n; j++)
		{
			if (arr[min] > arr[j])
			{
				min = j; // Record the subscript of the lowest value in the array 
			}
		}
		if (min != i)	//min be equal to i There is no need to exchange 
		{
			temp = arr[i];
			arr[i] = arr[min];
			arr[min] = temp;
		}
	}
}


/*
 Sorting by selection : From big to small 
 Here's how it works ： First, find the largest... In the unordered sequence （ Small ） Elements , To the beginning of the collating sequence ,
 then , Then continue to find the maximum from the remaining unordered elements （ Small ） Elements , Then put it in the row 
 End of sequence . And so on , Until all the elements are sorted .
*/
void sel_sort_b2s(int a[], int len)
{
#define SWAP(X,Y) X=X+Y;Y=X-Y;X=X-Y
	int max;
	for (int i = 0; i < len - 1; i++)
	{
		max = i;
		for (int j = i + 1; j < len; j++)
		{
			if (a[j] > a[max])
			{
				max = j;
			}
		}
		if (max != i)
		{
			SWAP(a[i], a[max]);
		}
	}
}

2、 Bubble sort

/*
 Bubble sort : From small to large 
 Here's how it works ： It repeatedly visits the sequence to be sorted , Compare two elements at a time , If they are in order （ : from large to small 、 First letter from A To Z） Mistakes are exchanged .
*/
void bubble_sort_s2b(int arr[], int len)
{
#define SWAP(X,Y) X=X+Y;Y=X-Y;X=X-Y
	for (int i = 0; i<(len - 1); i++)
	{
		for (int j = 0; j<(len - i - 1); j++)
		{
			if (arr[j] > arr[j + 1])
			{
				SWAP(arr[j], arr[j + 1]);
			}
		}
	}
}


/*
 Bubble sort : From big to small 
 Here's how it works ： It repeatedly visits the sequence to be sorted , Compare two elements at a time , If they are in order （ : from large to small 、 First letter from A To Z） Mistakes are exchanged .
*/
void bubble_sort_b2s(int arr[], int len)
{
#define SWAP(X,Y) X=X+Y;Y=X-Y;X=X-Y
	for (int i = 0; i<(len - 1); i++)
	{
		for (int j = 0; j<(len - i - 1); j++)
		{
			if (arr[j] < arr[j + 1])
			{
				SWAP(arr[j], arr[j + 1]);
			}
		}
	}
}