两个计数器来记录正数和负数的个数,最后保留11位小数。
import java.util.Scanner; // 注意类名必须为 Main, 不要有任何 package xxx 信息 public class Main { public static void main(String[] args) { Scanner in = new Scanner(System.in); int n = in.nextInt(); int[] a = new int[n]; for (int i = 0; i < n; i++) { a[i] = in.nextInt(); } double sum = 0.0; int cnt1 = 0; int cnt2 = 0; for (int i : a) { if (i < 0)cnt1++; if (i > 0) { sum += i; cnt2++; } } double avg = 0.0; if (cnt2 == 0) { avg = 0; } else { avg = sum / cnt2; } System.out.printf("%d %.11f", cnt1, avg); } }