4-2-7.c

#include <stdio.h>

int factorsum(int number);

void PrintPN(int m, int n);

int main() {
    int m, n;

    scanf("%d %d", &m, &n);
    PrintPN(m, n);

    return 0;
}

/* 你的代码将被嵌在这里 */
int factorsum(int number) {
    int sum = 1;

    if (1 == number)
        return 0;

    for (int i = 2; i <= number / 2; i++) {
        if (number % i == 0)
            sum += i;
    }

    return sum;
}

void PrintPN(int m, int n) {
    int flag = 0;
    for (int i = m; i <= n; i++)
        if (factorsum(i) == i) {
            flag = 1;
            printf("%d = 1", i);
            for (int j = 2; j <= i / 2; j++) {
                if (i % j == 0)
                    printf(" + %d", j);
            }
            printf("\n");
        }

    if (!flag)
        printf("None");
}