By a recursive algorithm, solving the combination of positive integers M

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

int Sum(int *buff, int len)
{
    int sum = 0;
    for (int i = 0; i < len; i++) {
        sum += buff[i];
    }
    return sum;
}

void Print(int *buff, int len)
{
    for (int i = 0; i < len; i++) {
        printf("%d ", buff[i]);
    }
    // printf("\n");
}

int Perm(int *buff, int *len, int start, int m, int *count)
{
    int sum = Sum(buff, *len);
    int min = ((m - sum) < start) ? (m - sum) : start;
    for (int i = min; i > 0; i--) {
        if ((sum + i) == m) {
            (*count)++;
            Print(buff,Only *);
            printf("%d\n", i);
            continue;
        }

        buff[*len] = i;
        (*len)++;

        Perm(buff, len, i, m, count);
        (*len)--;
    }
}

int main()
{
    int buff[10] = {0};
    int len = 0;
    int count = 0;
    int n;
    scanf("%d", &n);
    Perm(buff, &len, n, n, &count);
    printf("n = %d, count = %d\n", n, count);
    return 0;
}