java - 我的平均公式没有给出确切的答案

Question

这个问题已经有答案了:

Division of integers in Java [duplicate] (7 个回答)

已关闭 4 年前。

我创建了一个 Java 程序，它接受三个整数并打印总和、乘积、最小和最大以及这三个整数的平均值。

import java.util.Scanner;

public class ThreeNums
{
    public static void main (String[] args)
    {
        new ThreeNums();
    }

    public ThreeNums ()
    {
        int num1, num2, num3, sum, smallest, largest, exitPrompt = 0;
        float average;

        Scanner scan = new Scanner (System.in);

        while (exitPrompt == 0)
        {
            System.out.printf ("\n\nPlease enter three integers.\n");
            System.out.printf ("\t1st integer: ");
            num1 = scan.nextInt();
            System.out.printf ("\t2nd integer: ");
            num2 = scan.nextInt();
            System.out.printf ("\t3rd integer: ");
            num3 = scan.nextInt();
            System.out.printf ("\n");

            sum = num1+num2+num3;
            System.out.println ("Sum: " + sum);
            System.out.printf ("Product: %d\n", num1*num2*num3);

            if (num1<num2)
                smallest = num1;
            else
                smallest = num2;

            if (smallest<num3)
                smallest = smallest;
            else
                smallest = num3;

            if (num1>num2)
                largest = num1;
            else
                largest = num2;

            if (largest>num3)
                largest = largest;
            else
                largest = num3;

            System.out.printf ("Smallest integer: %d\n", smallest);
            System.out.printf ("Largest integer: %d\n", largest);

            average = sum/3;
            System.out.printf ("Average: %.3f\n", average);

            System.out.printf ("\nExit? 0 if NO, any other digit if YES\n");
            exitPrompt = scan.nextInt();
        }

        System.out.printf ("\n\n");
    }
}

一切都很好，除了(我认为)第 56-57 行:

average = sum/3;
System.out.printf ("Average: %.3f\n", average);

它应该打印用户输入的三个整数的平均值。例如，如果用户输入 5、7、7，则应该显示平均值为 6.333:

Please enter three integers.
1st integer: 5
2nd integer: 7
3rd integer: 7

Sum: 19
Product: 245
Smallest integer: 5
Largest integer: 7
Average: 6.333

Exit? 0 if NO, any other digit if YES

但是，对于平均值，它仅显示 6.000。

.
.
.
Average: 6.000
.
.

如果我输入 78、45 和 23，它只显示 48.000，而不是 48.667，依此类推。我的代码可能有什么问题？请帮忙...谢谢!

Answer 1

这里:average = sum/3; sum 和 3 都是 int，所以结果是一个 int，然后将其转换为 float。您可以通过以下方法克服这个问题:

average = sum / 3.0;