1.直接插入排序

//1.直接插入排序
#include<iostream>
using namespace std;
void insert_sort(int a[], int n)
{
	int i, j, temp;
	for (i = 1; i < n; i++)
	{
		temp = a[i];
		for (j = i-1 ; j >= 0 && temp < a[j]; j--)
		{
			a[j + 1] = a[j];
		//	a[j] = temp; //这一句和for循环外的a[j+1]=temp，重复，当退出循环是，j--，然后在a[j+1]=temp
			             //这和在循环中执行a[j]=temp的效果是一样的。
		}
		a[j+1] = temp;
	}
}

void print_array(int a[], int len)
{
	for (int i = 0; i < len; i++)
	{
		cout << a[i] << " ";
	}
	cout << endl;
}

int main()
{
	int a[] = { 7,3,5,8,9,1,2,4,6 };
	cout << "before insert sort: ";
	print_array(a, 9);
	insert_sort(a, 9);  //进行直接排序
	cout << "after insert sort: ";
	print_array(a, 9);
	return 0;
}

before insert sort: 7 3 5 8 9 1 2 4 6
after insert sort: 1 2 3 4 5 6 7 8 9

2.希尔(Shell)排序

//2.希尔(Shell)排序
#include<iostream>
using namespace std;

void shell_sort(int a[], int len)
{
	int h, i, j, temp;
	for (h = len / 2; h > 0; h = h / 2)  //控制增量
	{
		for (i = h; i < len; i++)   //这个for循环就是前面的直接插入排序
		{
			temp = a[i];
			for (j = i - h; j >= 0 && temp < a[j]; j-=h)
			{
				a[j + h] = a[j];
			}
			a[j + h] = temp;
		}
	}
}

void print_array(int a[],int len)
{
	for (int i = 0; i < len; i++)
	{
		cout << a[i] << " ";
	}
    cout << endl;
}

int main()
{
	int a[] = { 7,3,5,8,9,1,2,4,6 };
	cout << "before shell sort: ";
	print_array(a, 9);
	shell_sort(a, 9);
	cout << "after shell sort: ";
	print_array(a, 9);
	return 0;
}

before shell sort: 7 3 5 8 9 1 2 4 6
after shell sort: 1 2 3 4 5 6 7 8 9

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3.冒泡排序

//3.冒泡排序
#include<iostream>
using namespace std;
void bubble_sort(int a[], int len)
{
	int i = 0;
	int j = 0;
	int temp = 0;
	for (i = 0; i < len - 1; i++)
	{
		for (j = len - 1; j >= i; j--)
		{
			if (a[j] < a[j-1])
			{
				temp = a[j-1];
				a[j-1] = a[j];
				a[j] = temp;
			}
		}
	}
}
void print_array(int a[], int len)
{
	for (int i = 0; i < len; i++)
	{
		cout << a[i] << " ";
	}
	cout << endl;
}

int main()
{
	int a[] = { 7,3,5,8,9,1,2,4,6 };
	cout << "before bubble sort: ";
	print_array(a, 9);
	bubble_sort(a, 9);
	cout << "after bubble sort: ";
	print_array(a, 9);
	return 0;

}

before bubble sort: 7 3 5 8 9 1 2 4 6
after bubble sort: 1 2 3 4 5 6 7 8 9

4.快速排序

//4.快速排序
#include<iostream>
using namespace std;
void quick_sort(int a[], int low, int high)
{
	int i, j, pivot;
	if(low<high)
	{ 
	pivot = a[low];
	i = low;
	j = high;
	while (i < j)
	{
		while (i < j && a[j] >= pivot)
		{
			j--;
		}
		if (i < j)   //a[j]<pivot
			a[i++] = a[j];  //将比pivot小的元素移到低端
		while (i<j && a[i]<=pivot)
		{
			i++;
		}
		if (i < j)
		{
			a[j--] = a[i];
		}
	}
	a[i] = pivot;
	quick_sort(a, low,i - 1);
	quick_sort(a, i + 1, high);
   }
}

int main()
{
	int data[9] = { 54,38,96,23,15,72,60,45,83 };
	cout << "before quick sort: ";
	for (int i = 0; i < 9; i++)
		cout << data[i] << " ";
	cout << endl;
	cout << "after quick sort: ";
	quick_sort(data, 0, 8);
	for (int i = 0; i < 9; i++)
		cout << data[i] << " ";
	cout << endl;
	return 0;
}

before quick sort: 54 38 96 23 15 72 60 45 83
after quick sort: 15 23 38 45 54 60 72 83 96