C语言函数法求1000以内的全部水仙花数并判断求出的水仙花数是否为素数

以下是C语言函数法求1000以内的全部水仙花数并判断求出的水仙花数是否为素数的示例代码：

#include <stdio.h>
#include <math.h>

// 判断是否为水仙花数
int isNarcissistic(int num) {
    int sum = 0;
    int digit = 0;
    int temp = num;
    while (temp > 0) {
        digit = temp % 10;
        sum += pow(digit, 3);
        temp /= 10;
    }
    return sum == num;
}

// 判断是否为素数
int isPrime(int num) {
    if (num < 2) {
        return 0;
    }
    for (int i = 2; i <= sqrt(num); i++) {
        if (num % i == 0) {
            return 0;
        }
    }
    return 1;
}

int main() {
    // 求1000以内的水仙花数并判断是否为素数
    for (int i = 100; i < 1000; i++) {
        if (isNarcissistic(i)) {
            printf("%d is a narcissistic number. ", i);
            if (isPrime(i)) {
                printf("And it is also a prime number.\n");
            } else {
                printf("But it is not a prime number.\n");
            }
        }
    }
    return 0;
}

输出结果如下：

153 is a narcissistic number. But it is not a prime number.
370 is a narcissistic number. But it is not a prime number.
371 is a narcissistic number. But it is not a prime number.
407 is a narcissistic number. But it is not a prime number.