十大经典算法之二：冒泡排序（Bubble-Sort）

1. 算法步骤

比较相邻的元素。如果第一个比第二个大，就交换他们两个。

对每一对相邻元素作同样的工作，从开始第一对到结尾的最后一对。这步做完后，最后的元素会是最大的数。

针对所有的元素重复以上的步骤，除了最后一个。

持续每次对越来越少的元素重复上面的步骤，直到没有任何一对数字需要比较。

2.C/C++代码

/*The Author: Smile
Position: Algorithm Engineer
*/
#include <iostream>
using namespace std;

bool BubbleSort(int a[], int len);
bool Swap(int *a, int *b);

#define LEN 10
int main()
{
	int a[LEN] = { 123, 452, 63, 4, 25, 446, 67, 28, 977, 44 };

	cout << "排序前：";
	for (int i = 0; i < LEN; i++)
	{
		cout << a[i] << " ";
	}
	cout << endl;

	BubbleSort(a, LEN);

	cout << "排序后：";
	for (int i = 0; i < LEN; i++)
	{
		cout << a[i] << " ";
	}

	return 0;
}

bool BubbleSort(int a[], int len)
{
	/*Steps of bubble sort :
		Compare adjacent elements. If the first is larger than the second, swap them both.
		Do the same for each pair of adjacent elements, from the first pair at the beginning to the last pair at the end. After this step is done, the last element will be the largest number.
		Repeat for all elements except the last one.
		Continue to repeat the above steps for fewer and fewer elements each time until there is no pair of numbers to compare.
	*/
	for (int i = 0; i < len - 1 ; i++)
	{
		for (int j = 0; j < len - i - 1; j++)
		{
			if (a[j] > a[j+1])
			{
				Swap(&a[j], &a[j+1]);
			}
		}

	}

	return true;
}

bool Swap(int *a, int *b)
{
	int temp;
	temp = *a;
	*a = *b;
	*b = temp;

	return true;
}