c - 任意数量数字的平均值

Question

我目前正在尝试为类作业创建一个 C 程序，该程序取任意数量的测试分数的平均值。但是，我遇到了一些问题。

我的教授提供了一个大纲来帮助入门。我也只能在指示的地方添加代码，因此没有额外的变量等。

这是我到目前为止所拥有的:

#include <stdio.h>

void calculateAverage()
{
    int grade, count, sum;
    double average;

/*     add code to input grades, calculate average, and print it */
/* --> between here */

printf("Enter the amount of test scores.\n");
scanf("%d", &count);

grade = 0;
sum = 0;

while (grade != -1 && grade <= 100 && grade >= 0)
{
    printf("Enter the grade. Enter -1 when you are done entering grades.\n");
    scanf("%d", &grade);

    if (grade != -1 && grade <= 100 && grade >= 0)
    {           
        sum = sum + grade;      
    }

    else
    {
        average = (sum / count);

        printf("average is %.2lf \n", &average);
    }

}
/* --> and here */
}

int main(void)
{
    while (1)
        calculateAverage();
return 0;
}

所以我遇到的问题是，到目前为止，平均值将始终被计算为 0。到底为什么会发生这种情况，我该如何解决它，以便它给我正确的平均值？

更新因此，我尝试将平均值转换为双倍，这样我就可以避免类型不匹配，这确实消除了编译器警告，但所有输入值的平均值仍然为 0。

#include <stdio.h>

void calculateAverage()
{
    int grade, count, sum;
    double average;

/*     add code to input grades, calculate average, and print it */
/* --> between here */

printf("Enter the amount of test scores.\n");
scanf("%d", &count);

grade = 0;
sum = 0;

while (grade != -1 && grade <= 100 && grade >= 0)
{
    printf("Enter the grade. Enter -1 when you are done entering grades.\n");
    scanf("%d", &grade);

    if (grade != -1 && grade <= 100 && grade >= 0)
    {           
        sum = sum + grade;      
    }

    else
    {

        average = (double)(sum / count);

        printf("average is %.2f \n", &average);
    }

}
/* --> and here */
}

int main(void)
{
    while (1)
        calculateAverage();

return 0;
}

Answer 1

#include <stdio.h>

void calculateAverage()
{
    int grade, count, sum;
    double average;

/*     add code to input grades, calculate average, and print it */
/* --> between here */

printf("Enter the amount of test scores.\n");
scanf("%d", &count);

grade = 0;
sum = 0;

while (grade != -1 && grade <= 100 && grade >= 0)
{
    printf("Enter the grade. Enter -1 when you are done entering grades.\n");
    scanf("%d", &grade);

    if (grade != -1 && grade <= 100 && grade >= 0)
    {           
        sum = sum + grade;      
    }

    else
    {

        average = (double)(sum / count);

        printf("average is %.2lf \n", average);  #  <---- Please fix this!
    }

}
/* --> and here */
}

int main(void)
{
    while (1)
        calculateAverage();

return 0;
}

您的代码中存在一些问题:

1. 其中之一是您正在使用 & 运算符打印平均值的地址。
   
2. 您可以更改的另一件事是在打印 double 时使用正确的格式说明符。