标准偏差Java [关闭]

Question

我必须编写一个程序，读取一组浮点值（总共 10 个。它是固定的），然后计算并显示这些值的平均值、标准差、最小值、最大值, 第二大的值 它应该有一个循环。在循环中，提示用户输入一个数字（一个可以有小数部分的浮点数）并将该数字保存在一个变量中（双精度型）。我已经做到了，但是在实现循环以更容易地获取值时遇到了麻烦，因为我不知道如何在通过循环计算时保存它们。所以现在我的代码看起来非常丑陋和多余。

import java.util.Scanner;

public class Statistics {

    public static void main(String[] args){
        Scanner s = new Scanner(System.in);
        float average = 0;
        float smallest = 0;
        float largest = 0;
        float scndLargest = 0;
        float a, b, c, d, e, f, g, h, i, j = 0;
        System.out.println("Enter values.");
        a = s.nextFloat();
        b = s.nextFloat();
        c = s.nextFloat();
        d = s.nextFloat();
        e = s.nextFloat();
        f = s.nextFloat();
        g = s.nextFloat();
        h = s.nextFloat();
        i = s.nextFloat();
        j = s.nextFloat();

        average = (a + b + c + d + e + f + g + h + i + j) / 10;
        float min1 = Math.min(a, b);
        float min2 = Math.min(c, d);
        float min3 = Math.min(e, f);
        float min4 = Math.min(g, h);
        float min5 = Math.min(i, j);

        float min6 = Math.min(min1, min2);
        float min7 = Math.min(min3, min4);
        float min8 = Math.min(min7, min5);

        smallest = Math.min(min6, min8);
        System.out.println("The smallest value is: " + smallest);

        float max1 = Math.max(a, b); //2
        float max2 = Math.max(max1, c);
        float max3 = Math.max(max2, d); //4
        float max4 = Math.max(max3, e);
        float max5 = Math.max(max4, f); //6
        float max6 = Math.max(max5, g); //6
        float max7 = Math.max(max6, h); //8
        float max8 = Math.max(max7, i);
        largest = Math.max(max8, j); //10

        System.out.println("The largest value is: " + largest);

        scndLargest = Math.min(largest, max8);
        System.out.println("The second largest value is: " + scndLargest);
        System.out.println("The average of all the values is: " + average);

        double a1 = Math.pow(a - average, 2);
        double b1 = Math.pow(a - average, 2);
        double c1 = Math.pow(a - average, 2);
        double d1 = Math.pow(a - average, 2);
        double e1 = Math.pow(a - average, 2);
        double f1 = Math.pow(a - average, 2);
        double g1 = Math.pow(a - average, 2);
        double h1 = Math.pow(a - average, 2);
        double i1 = Math.pow(a - average, 2);
        double j1 = Math.pow(a - average, 2);

        double sum1 = Math.pow(a1 /10, 2);
        double sum2 = Math.pow(b1 /10, 2);
        double sum3 = Math.pow(c1 /10, 2);
        double sum4 = Math.pow(d1 /10, 2);
        double sum5 = Math.pow(e1 /10, 2);
        double sum6 = Math.pow(f1 /10, 2);
        double sum7 = Math.pow(g1 /10, 2);
        double sum8 = Math.pow(h1 /10, 2);
        double sum9 = Math.pow(i1 /10, 2);
        double sum10 = Math.pow(j1 /10, 2);

        double total = (sum1 + sum2 + sum3 + sum4 + sum5 + sum6 + sum7 + sum8 + sum9 + sum10);
        double squaredVariance = (total) / 10;
        double newTotal = Math.sqrt(squaredVariance);
        System.out.printf("Standard deviation is: ");
        System.out.printf("%.2f", newTotal);


    }

}

Answer 1

不要命名每个变量，而是尝试array

float inputs = new float[10];
for(int i = 0; i < inputs.length; i++)
    inputs[i] = s.nextFloat();

一旦你有了一个数组，你也可以通过循环找到最小值

float min = inputs[0];
for(float f : inputs)
    min = Math.min(f, min);

如果你想变得花哨，你也可以使用流来找到最小值/最大值（可能只适用于双精度数组）

double min = Arrays.stream(inputs).min().getAsDouble();

Answer 2

我重写了整个课程，因为我目前在 CompSci 和统计专业，所以它引起了我的兴趣。

import java.util.Arrays;
import java.util.Scanner;

class Main {

  static float[] input = new float[10];
  static Scanner s = new Scanner(System.in);

  public static void main(String[] args) {

    for(int i = 0; i < 10; i++) {
      input[i] = s.nextFloat();
    }
    Arrays.sort(input);

    System.out.println("Largest: " + input[9]);
    System.out.println("Smallest: " + input[0]);
    System.out.println("Second largest: " + input[8]);
    System.out.println("Average: " + getTotal()/10);
    System.out.printf("Standard deviation %.2f", Math.sqrt(getTotal()/10));
  }

  static public float getTotal() {
    float total = 0;

    for(int i = 0; i < 10; i++) {
      total += input[i];
    }

    return total;
  }
}