为什么我写的希尔排序不运行呢？c语言

Question

#include <stdio.h>
void swap(int arr[],int a,int b)
{int temp=arr[a];
arr[a]=arr[b];
arr[b]=temp;
}
void shellsort(int arr[],int n)
{ int i,j,temp,a;
for(a=n/2;a>0;a=a/2)
{ for(i=a;i<n;i++)
{
for(j=i-a;j-=a;j>=0)
{
if(arr[j+a]<arr[j])
{ swap (arr,j+a,j);}
}
}
}
}
#define n 8
int main( )
{ int i;
int arr[n] = {6,5,3,1,8,7,2,4};
for(i=0;i<8;i++)
printf("%d",arr[i]); //输出排序前的所有数组元素
printf("\n");
shellsort(arr,n); //直接调用前面定义的希尔排序函数
for(i=0;i<n;i++)
printf("%d", arr[i]); //输出排序后的所有数组元素

}

Answer 1

#include <iostream>
#include <vector>

using namespace std;

vector<int> ShellSort(vector<int> list){
    vector<int> result = list;
    int n = result.size();
    for (int gap = n >> 1; gap > 0; gap >>= 1){
        for (int i = gap; i < n; i++){
            int temp = result[i];
            int j = i - gap;
            while (j >= 0 && result[j] > temp){
                result[j + gap] = result[j];
                j -= gap;
            }
            result[j + gap] = temp;
        }
        for (int i = 0; i < result.size(); i++){
            cout << result[i] << " ";
        }
        cout << endl;
    }
    return result;
}

void main(){
    int arr[] = { 6, 4, 8, 9, 2, 3, 1 };
    vector<int> test(arr, arr + sizeof(arr) / sizeof(arr[0]));
    cout << "排序前" << endl;
    for (int i = 0; i < test.size(); i++){
        cout << test[i] << " ";
    }
    cout << endl;
    vector<int> result;
    result = ShellSort(test);
    cout << "排序后" << endl;
    for (int i = 0; i < result.size(); i++){
        cout << result[i] << " ";
    }
    cout << endl;
    system("pause");
}