c语言-快速排序

这个是升序排列，如果想降序排列,将下面两行的符号反过来即可;
arr[right] <= arr[key]
arr[left] >= arr[key]
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代码工程

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>

void swap(int *v1, int *v2)
{
	int temp = *v1;
	*v1 = *v2;
	*v2 = temp;
}

void my_qsort(int *arr, int start, int end)
{
	int key = start;
	int left = start;
	int right = end;

	if (left > right)
	{
		return;
	}

	while (left < right)
	{
		/*从右往左遍历，找到小于arr[key]的值*/
		while ((left < right) && (arr[right] >= arr[key]))
		{
			right--;
		}
		/*从左往右遍历，找到大于arr[key]的值*/
		while ((left < right) && (arr[left] <= arr[key]))
		{
			left++;
		}
		/*交换值*/
		swap(&arr[left], &arr[right]);
	}

	swap(&arr[key], &arr[right]);
	
	key = right;

	my_qsort(arr, start, key - 1);

	my_qsort(arr, key + 1, end);

	return;
}


int main()
{
	int i = 0;
	int arr[] = { 10, 6, 9, 1, 8, 7, 5, 4, 2, 3 };
	int num = sizeof(arr) / sizeof(int);

	my_qsort(arr, 0, num - 1);

	printf("排序后：");

	for (i = 0; i < num; i++)
	{
		printf("%d ", arr[i]);
	}

	printf("\n");

	return 0;
}
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运行结果