C++插入排序算法

#include <iostream>

void insertion_sort(int arr[], int length)
{
    for (int i = 1; i < length; i++) {
        int key = arr[i];
        int j = i - 1;

        while (j >= 0 && arr[j] > key) {
            arr[j + 1] = arr[j];
            j -= 1;
        }
        
        arr[j + 1] = key;
    }
}

int main()
{
    int arr[] = {56,32,45,12,52,32,61,8,5,4,2,1};
    insertion_sort(arr, sizeof(arr) / sizeof(arr[0]));

    for (auto num : arr)
        std::cout << num << " ";
    std::cout << std::endl;
}