使用选择法对数组的10个整数按照从大到小的顺序进行排序

好的，下面是一个示例代码，使用选择排序算法对数组进行排序，并按照从大到小的顺序输出排序后的数组元素：

#include <iostream>
using namespace std;

void selectionSort(int arr[], int n) {
    int i, j, max_idx;
 
    // One by one move boundary of unsorted subarray
    for (i = 0; i < n-1; i++) {
        // Find the maximum element in unsorted array
        max_idx = i;
        for (j = i+1; j < n; j++) {
            if (arr[j] > arr[max_idx]) {
                max_idx = j;
            }
        }
        // Swap the found maximum element with the first element
        int temp = arr[i];
        arr[i] = arr[max_idx];
        arr[max_idx] = temp;
    }
}

int main() {
    int arr[] = {23, 54, 12, 6, 87, 34, 98, 65, 43, 21};
    int n = sizeof(arr)/sizeof(arr[0]);
    
    cout << "Original Array: ";
    for (int i = 0; i < n; i++) {
        cout << arr[i] << " ";
    }
    cout << endl;
    
    selectionSort(arr, n);
    
    cout << "Sorted Array: ";
    for (int i = 0; i < n; i++) {
        cout << arr[i] << " ";
    }
    cout << endl;
    
    return 0;
}

输出结果为：

Original Array: 23 54 12 6 87 34 98 65 43 21 
Sorted Array: 98 87 65 54 43 34 23 21 12 6 

这段代码会先输出原始的数组，然后对数组进行选择排序，最后输出排序后的数组元素，按照从大到小的顺序排列。