double 的格式化 输出

// poj 2350import java.io.*;import java.util.*;import java.text.DecimalFormat; // add this.public class Main {public static void main(String[] args) {Scanner cin = new Scanner(System.in);int[] a = new int[1010];int ans, sum, i, n, Case, testCase;testCase = cin.nextInt();for (Case = 0; Case < testCase; ++Case) {n = cin.nextInt();for (i = sum = 0; i < n; ++i) {a[i] = cin.nextInt();sum += a[i];}for (i = ans = 0; i < n; ++i)if (a[i] * n > sum)++ans;DecimalFormat df = new DecimalFormat("0.000"); // notice hereSystem.out.println(df.format((double) (ans * 100.0) / n) + "%");}}}