Question

package gradeAvg;
import java.util.Scanner;
//Grade Average calculater
public class GradeAvg {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        System.out.print("Please Enter the first grade being added to the average:");
        double average = input.nextInt();
        System.out.print("The average is now: " + average + " Please enter the second grade being averaged:");
        average += input.nextInt() ;
        System.out.print("The average is now: " + average + " Please enter the third grade being averaged:");
        average += input.nextInt() / 2;
        System.out.print("The average is now: " + average + " Please enter the fourth grade being averaged:");
        average += input.nextInt() / 2;
        System.out.print("The average is now: " + average + " Please enter the fifth grade being averaged:");
        average += input.nextInt() / 2;
        input.close();
        System.out.print(average);




    }

}

嘿伙计们，我是java的新手，在数学方面非常糟糕，我应该制作一个允许用户输入值的程序，将其平均化，打印出来，然后允许输入另一个值，进行平均，打印，然后继续。当我在每次输入结束时除以2或者什么时，我会出错？

Answer 1

平均值是所有数字的总和除以总和中的数字数。

你在这里做的不是平均的。您将每个新数字的一半添加到总和中。我不知道你在这做什么。

为了让事情更容易理解，让我们制作sum和counter：

public class GradeAvg {

    public static void main(String[] args) {
        int sum;
        int counter;
        // ...
    }

}

每当您要求提供号码时，您都会增加计数器并将新号码添加到sum：

int newNumber;
// ask for input
newNumber = input.nextInt()
sum += newNumber;
counter++;

然后您可以输出这样的平均值：

System.out.println("The average is: " + (double)sum / counter);

Answer 2

那是错的。你添加的每个数字与其他数字相比增加了50％。你需要跟踪计数（元素的数量）和总和，每次将总和除以元素的数量。所以每次添加数字时，函数都应该是：

（OLD_AVERAGE * OLD_COUNT + NEW_NUMBER）/（OLD_COUNT + 1）

或者只使用SUM和COUNT，每次AVERAGE = SUM / COUNT。 INC。每新数字都会计数1。按输入的数字加总。

Answer 3

完整的工作解决方案......希望它有所帮助...

public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    double sum = 0;
    int count = 1;
    double average = 0;
    System.out.print("Please Enter the " + count + " grade being added to the average:");
    for (; count <= 5;) {
        sum = sum + input.nextInt();
        average = sum / count;
        System.out.println("The average is now: " + average);
        count++;
        if (count <= 5)
            System.out.println("Please enter the " + count + " grade being averaged:");
    }
    input.close();
}

每次添加某些内容时都要尝试取平均值

3 个答案: