Question

我是递归新手，有人可以赐教。

问题是：

找到＃101的学生测验的平均成绩。＆＃34;

我已经使用迭代解决了它，但我不知道如何将其转换为递归。

import java.io.*; 
import java.util.*;

public class Test{
    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        Scanner sc = new Scanner(System.in);

        String arr[][] = {{"101","Quiz","90"},{"101","CS","80"},{"102","Quiz","85"},{"101","Quiz","75"},{"103","CS","84"},{"101","Quiz","87"}};
        int sum = 0;
        int ave = 0;
        System.out.println("Student #\tType\tGrade");
        for(int ctr = 0; ctr<arr.length; ctr++){
            System.out.println(arr[ctr][0]+"\t\t"+arr[ctr][1]+"\t"+arr[ctr][2]);

            if(arr[ctr][0] == "101"){
                if(arr[ctr][1] == "Quiz"){
                    sum += Integer.parseInt(arr[ctr][2]);
                    ave += 1;
                }
            }

        }
        System.out.println("The Average quiz of Student # 101 is: "+ sum/ave);


    }



}

Answer 1

你可以做这样的事情，但我不认为它是优雅/实用/良好的做法：

public int[] recursiveAverage(String array[][], int i){
    if (i < array.length)
    {
        int[] previousAverage = recursiveAverage(array, i + 1);
    }
    else
    {
        int[] previousAverage = {0, 0};
    }

    if (array[i][0] == "101" && array[i][1] == "Quiz")
    {
        previousAverage[0] = Integer.parseInt(array[i][2]);
        ++previousAverage[1];
    }

    return previousAverage;
}

然后您将previousAverage[0]除以previousAverage[1]以获得实际平均值。这实际上是你的迭代函数，用递归代替for循环。

要有创意。

转换为递归方法

1 个答案: