c++中如何把列表中每个整数分解质因数，然后将所有的质因子存储到一个集合中，最后返回这个集合

下面是一个C语言程序，可以将一个整数列表中的每个整数分解质因数，然后将所有的质因子存储到一个集合中，最后返回这个集合：

#include <stdio.h>
#include <stdlib.h>

#define MAX_PRIME_NUM 1000

int is_prime(int n) {
    if (n <= 1) {
        return 0;
    }
    for (int i = 2; i*i <= n; i++) {
        if (n % i == 0) {
            return 0;
        }
    }
    return 1;
}

void prime_factors(int n, int *factors, int *num_factors) {
    int p = 2;
    while (n > 1) {
        if (n % p == 0) {
            factors[(*num_factors)++] = p;
            n /= p;
        } else {
            p++;
            while (!is_prime(p)) {
                p++;
            }
        }
    }
}

void prime_set(int *nums, int len, int *prime_nums, int *num_prime_nums) {
    int factors[MAX_PRIME_NUM];
    int num_factors = 0;
    for (int i = 0; i < len; i++) {
        prime_factors(nums[i], factors, &num_factors);
    }
    for (int i = 0; i < num_factors; i++) {
        int prime = factors[i];
        int found = 0;
        for (int j = 0; j < *num_prime_nums; j++) {
            if (prime == prime_nums[j]) {
                found = 1;
                break;
            }
        }
        if (!found) {
            prime_nums[(*num_prime_nums)++] = prime;
        }
    }
}

int main() {
    int nums[] = {12, 15, 21, 24, 28};
    int num_nums = sizeof(nums) / sizeof(nums[0]);

    int prime_nums[MAX_PRIME_NUM];
    int num_prime_nums = 0;

    prime_set(nums, num_nums, prime_nums, &num_prime_nums);

    printf("Prime factors:\n");
    for (int i = 0; i < num_prime_nums; i++) {
        printf("%d\n", prime_nums[i]);
    }

    return 0;
}

运行结果：

Prime factors:
2
3
5
7