插入排序（正序、倒序）-c++代码实现及运行实例结果

#include <iostream>

using namespace std;

void insertion_sort(int arr[], int length);

int main()
{
int Arr[] = { 2, 1, 5, 7, 3, 4, 8, 6 };
int len = sizeof (Arr) / sizeof (Arr[0]);

cout << "before"<<endl;
for (int i = 0; i < len; i++)    {
cout <<  Arr[i] << " ";
}
cout<<endl;

insertion_sort(Arr, len);
cout << "after"<<endl;
for (int j = 0; j < len; j++)    {
cout << Arr[j] << " ";
}
cout << endl;

return 0;
}

void insertion_sort(int arr[], int length)
{
int i, j, key;
for (i = 1; i < length; i++){
key = arr[i];
for (j = i - 1; j >= 0; j--){
if (arr[j] > key) {
arr[j + 1] = arr[j];
}
else
break;
}
arr[j + 1] = key;
}
}

if (arr[j] > key)

if (arr[j] < key)