C语言代码把数组按照元素个数由多到少排序。 例如数组：[1,2,5,3,2], 排序后，输出[2,2,1,5,3]

以下是使用 C 语言实现将数组按照元素个数由多到少排序的代码：

#include <stdio.h>

#define MAX_SIZE 100

int main() {
    int arr[MAX_SIZE], freq[MAX_SIZE];
    int n, i, j, temp;

    printf("Enter the size of the array: ");
    scanf("%d", &n);

    printf("Enter the elements of the array:\n");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
        freq[i] = -1;
    }

    for (i = 0; i < n; i++) {
        int count = 1;
        for (j = i + 1; j < n; j++) {
            if (arr[i] == arr[j]) {
                count++;
                freq[j] = 0;
            }
        }
        if (freq[i] != 0) {
            freq[i] = count;
        }
    }

    for (i = 0; i < n - 1; i++) {
        for (j = i + 1; j < n; j++) {
            if (freq[i] < freq[j]) {
                temp = freq[i];
                freq[i] = freq[j];
                freq[j] = temp;

                temp = arr[i];
                arr[i] = arr[j];
                arr[j] = temp;
            }
        }
    }

    printf("The array sorted by frequency of elements (from high to low):\n");
    for (i = 0; i < n; i++) {
        printf("%d ", arr[i]);
    }

    return 0;
}

运行程序后，输入数组的大小和元素，程序将输出按照元素个数由多到少排序后的数组。