Question

当我运行此代码并输入总和> 100的数字时，输出对于计数和总和是正确的但平均值是错误的。例如;输入8,10,99 ...计数为3，总和为117，应返回平均值39 ...返回的实际输出为计数3，总和117和平均值58.5。我已经意识到这是因为平均值是使用2而不是3来计算（或者总是比使用不同值的值少一个）。为什么是这样？它适用于输入和<= 100。请帮助:)）

 public static void main(String[] args) {
    //Use Main Method for gathering input
    float input = 1;
    // Declare variable for sum
    float theSum = 0;
    // Declare variable for average
    float average = 0;
    // Declare variable for counting the number of user inputs
    int counter = 0;
    /* Initialize the while loop using an input of 0 as a sentinel value
     * to exit the loop*/
    while (input != 0) {
        // Use JOptionPane method to accept input from user
        input = Float.parseFloat(
                JOptionPane.showInputDialog(
                null, "Please enter a number.  Enter 0 to quit: "));
        // Invoke sum method and pass input and summation to sum method
        theSum = (sum(input, theSum));
        // Invoke avg method and pass summation and counter to avg
        average = (avg(theSum, counter));
        // Increment the counter variable
        counter++;

        if (theSum > 100)
        {
            JOptionPane.showMessageDialog(null, "The sum of your numbers "
                    + "are greater than 100!");
            break;
        }
    }
        // Invoke display method and pass summation, average, and counter variables to it
        display(theSum, average, counter);
    }


public static float sum(float num1, float sum) {
    //Add the user's input number to the sum variable
    sum += num1;
    //Return value of sum variable as new summation variable
    return sum;
}

public static float avg(float num1, int num2) {
    //Declare and initialize variable for average
    float average = 0;
    //Calculate average
    average = num1 / num2;
    //Return value of average variable
    return average;
}

public static void display(float sum, float average, int counter) {

    /* I am subtracting 1 from variable counter so as not to include the sentinel value
     * of 0 that the user had to enter to exit the input loop in the overall count*/

    // Display the count, sum, and average to the user
    if (sum > 100) {
        JOptionPane.showMessageDialog(null, "Count = " + (counter) + ", Sum = " + sum + ", Average = " + average);
    }
    if (sum <= 100) {
        JOptionPane.showMessageDialog(null, "Count = " + (counter - 1) + ", Sum = " + sum + ", Average = " + average);
    }

}

}

Answer 1

在取平均值后递增计数器，这就是为什么你会看到基于2个数字而不是预期值3的平均值。

average = (avg(theSum, counter)); // Increment the counter variable counter++;

交换这两个并在取平均值之前递增计数器。

counter++; // Increment the counter variable average = (avg(theSum, counter));

修改

以下是您应该更改的内容：

首先，仅在输入不是= 0
时才更新计数器
if(input!=0) { counter++; }

其次，将平均代码移出循环，并在显示之前将其放在最后，不需要反复计算平均值。

average = (avg(theSum, counter)); display(theSum, average, counter);

第三，从counter-1方法移除display并打印counter

public static void display(float sum, float average, int counter) { JOptionPane.showMessageDialog(null, "Count = " + (counter) + ", Sum = " + sum + ", Average = " + average); }

之后，它适用于您期望的两种情况

你能帮我修一下我代码的平均部分吗？

1 个答案: