Question

我正在尝试编写一个执行以下操作的程序。

1）提示用户输入整数并存储它。 2）使用用户输入来计算 *算术平均值 *几何平均数 *他们刚输入的号码的最小值和最大值。

我已经做了大部分工作，从我看到的，我向用户询问输入并将其存储在变量userInput下第一种方法。

我不确定如何使用userInput进行算术平均值，几何平均值以及最小值和最大值。

public class SimpleStatistics {

    public static double[] getUserInput() {
        // Returns a string of doubles
        Scanner sc = new Scanner(System.in);

        // Create list
        List<Double> inputList = new ArrayList<Double>();

        // Getting input
        System.out.println("Please enter number");
        double userInput = sc.nextDouble();

        // See our new list
        System.out.println(inputList);
        double arr[] = new double[inputList.size()];
        System.out.println(inputList.size());
        return arr;
    }

    public static double arithmeticMean(double[] nums) {

        double mean = 0;
        double sum = 0;

        for (int i = 0; i < nums.length; i++) {
            sum = sum + nums[i];
        }
        mean = sum / nums.length;

        return mean;
    }

    public static double geometricMean(double[] nums) {

        double gm = 1.0;
        for (int i = 0; i < nums.length; i++) {
            gm *= nums[i];
        }
        gm = Math.pow(gm, 1.0 / (double) nums.length);
        return gm;
    }

    public static double[] minAndmax(double[] nums) {

        double min = nums[0];
        double max = nums[0];

        for (int i = 1; i < nums.length; i++) {
            if (nums[i] < min) {
                min = nums[i];
            } else if (nums[i] > max) {
                max = nums[i];
            } else {

            }
        }

        double[] minAndmax = { min, max };
        return minAndmax;
    }

    public static double[] scaleUp(double[] nums, int factor) {

        for (int i = 0; i < nums.length; i++) {
            nums[i] *= factor;
        }
        return nums;
    }

    public static double[] scaleDown(double[] nums, int factor) {

        for (int i = 0; i < nums.length; i++) {
            nums[i] /= factor;
        }
        return nums;
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        double[] input = { 1, 2.8, 5.3, 100, -5, -6.5 };

        System.out.println("Choose a option 1-6");

        boolean exit = false;
        while (!exit) {
            System.out.println();
            System.out
                    .println("1) Arithmetic mean, 2) Geometric mean, 3)  minAndmax, 4)  Scale Up, 5)  Scale Down, 6)  Quit");
            System.out.print("Input -> ");
            int choice = sc.nextInt();
            System.out.println();

            switch (choice) {
            case 1: {
                // Arithmetic mean
                System.out.println("Arithmetic mean");
                System.out.println(arithmeticMean(input));
                break;
            }
            case 2: {
                // Geometric mean
                System.out.println("Geometric mean");
                System.out.println(arithmeticMean(input));
                break;
            }
            case 3: {
                // Min and max
                System.out.println("Min and Max");
                for (double i : minAndmax(input)) {
                    System.out.print(i + ", ");
                }
                break;
            }
            case 4: {
                // Scale Up
                System.out.println("Scale Up");
                System.out
                        .print("Please enter factor by which you want to scale -> ");
                int factor = sc.nextInt();
                for (double i : scaleUp(input, factor)) {
                    System.out.print(i + ", ");
                }
                break;
            }

            case 5: {
                // Scale Down
                System.out.println("Scale Down");
                System.out
                        .print("Please enter factor by which you want to scale -> ");
                int factor = sc.nextInt();
                for (double i : scaleDown(input, factor)) {
                    System.out.print(i + ", ");
                }
                break;
            }

            case 6: {
                exit = true;
                break;
            }

            }
        }
    }
}

Answer 1

您实际上并没有将数字添加到双数组中。将getUserInput（）函数更改为以下内容：

public static double[] getUserInput() {

    Scanner sc = new Scanner(System.in);

    System.out.println("How many numbers are you entering?");
    double[] arr = new double[sc.nextInt()];

    for (int i = 0; i < arr.length; i++) {
        System.out.println("Please enter your number");
        arr[i] = sc.nextDouble();
    }
    sc.close();

    return arr;
}

Answer 2

将getUserInput方法更改为：

public static double[] getUserInput() {

    Scanner sc = new Scanner(System.in);

    List<Double> inputList = new ArrayList<Double>();

    System.out.println("Please enter how many numbers you will be inputing");
    int numberOfInputs = sc.nextInt();

    for (int i = 0; i < numberOfInputs; i++) {
        System.out.println("Please enter a number");
        double userInput = sc.nextDouble();
        inputList.add(userInput);
    }
    sc.close();

    double[] arr = new double[inputList.size()];
    for (int i = 0; i < arr.length; i++) {
        arr[i] = inputList.get(i);
    }
    return arr;
}

然后，在main方法中，通过调用方法来使用输入。 E.g。

// Arithmetic mean
System.out.println("Arithmetic mean");
System.out.println(arithmeticMean(getUserInput()));
break;

我很乐意提供帮助，请询问是否还有其他事项。

（Java）统计程序

2 个答案: