Question

我的代码有两个问题。 1）当我向我的arraylist添加值时，它没有给我正确的平均值所以我知道我的for循环中的条件是关闭的2）它没有显示我的arrayList中的所有数字。它特别不显示第0个整数。

这是我的代码：

public class CalcAvgDropSmallest {  

    public static void main(String[] args) {       
       int lowNum = 0;  // # of the lowest numbers to be dropped
       double average;  // calcuates the mean of the sum and the lowest numbers dropped
       ArrayList<Double> inputs= getALInfo();
       lowNum = getLowestnum();
       average = calculateAvg(inputs, lowNum);
       getAvg(inputs, lowNum, average);

    }

    public static ArrayList<Double> getALInfo() {
        ArrayList<Double> inputs = new ArrayList<Double>(); 

        // Read Inputs
          Scanner in = new Scanner(System.in);
          System.out.println("Please enter 5 - 10 integers, Q to quit: ");         
          Double vals = in.nextDouble();

         while (in.hasNextDouble())
            {
               inputs.add(in.nextDouble());
            }             

        return inputs;     
    }   

    public static int getLowestnum() {        
        int lowNum = 0;

        // Reads Input value for # of lowest values dropped

        System.out.println("How many of the lowest values should be dropped?");
        Scanner in = new Scanner(System.in);
        lowNum = in.nextInt();

        return lowNum;

    }

    public static double calculateAvg(ArrayList<Double> inputs, int lowNum) {
        double sum = 0;
        double average = 0;                
        int i = 0;
        // Calcuates the average of the array list with the lowest numbers dropped

        for (i = 0; i < inputs.size(); i++) 
        {
            if (inputs.get(i) > lowNum) {
                sum = sum + inputs.get(i);
            }
        }
        average = (sum / inputs.size());        

       return average;
    }

    public static void getAvg(ArrayList<Double> inputs,int n, double average) {
       // It's adding all the values and dividing by the size of it, which is a problem
       // Also, it's not showing the 0th integer aand just straight to the 1st integer
      System.out.println("The average of the numbers " + inputs + " except the lowest " +n+ " is " +average);  
    }
}

Answer 1

首先，请编程到function doRequest(url) { return new Promise(function (resolve, reject) { request(url, function (error, res, body) { if (!error && res.statusCode == 200) { resolve(body); } else { reject(error); } }); }); } // Usage: async function main() { let res = await doRequest(url); console.log(res); } main();界面（而不是List具体类型）。其次，您应该确保将读取的每个值添加到ArrayList。然后，确保你读取终止值（并丢弃它）;否则它将在缓冲区中挂起。最后，我将List传递给方法（而不是在本地重新声明）。像，

Scanner

您可以简化public static List<Double> getALInfo(Scanner in) { List<Double> inputs = new ArrayList<>(); System.out.println("Please enter 5 - 10 integers, Q to quit: "); while (in.hasNextDouble()) { inputs.add(in.nextDouble()); } in.next(); return inputs; }之类的

getLowestnum

然后，您的public static int getLowestnum(Scanner in) { System.out.println("How many of the lowest values should be dropped?"); return in.nextInt(); }应对calculateAvg进行排序并获取List（丢弃subList值），最后返回平均值。像，

lowNum

然后public static double calculateAvg(List<Double> inputs, int lowNum) { Collections.sort(inputs); return inputs.subList(lowNum, inputs.size()).stream() .mapToDouble(Double::doubleValue).average().getAsDouble(); }完成示例

main

ArrayList通过删除最小值来计算平均值

1 个答案: