计算工作不正常

Question

我正在从一本名为“C by Example”的书中学习 C

在每一章的末尾都有一个练习需要完成。从下面的代码可以看出，练习写在最上面

/* Chapter 7 Review Exercises #2
- You are a college professor and you have to get the average grades for 10 students. Write a program which prompts you for 10 different grades and then
displays their average */

#include <stdio.h>

int main()
{

    float score1, score2, score3, score4, score5, score6, score7, score8, score9, score10;

    float average = score1+score2+score3+score4+score5+score6+score7+score8+score9+score10/10;

    printf("Please input the scores of the students: \n");
    scanf(" %f",&score1);
    scanf(" %f",&score2);
    scanf(" %f",&score3);
    scanf(" %f",&score4);
    scanf(" %f",&score5);
    scanf(" %f",&score6);
    scanf(" %f",&score7);
    scanf(" %f",&score8);
    scanf(" %f",&score9);
    scanf(" %f",&score10);

    printf("The average score is: %.2f" , average);

    return 0;

}

这里的问题是每次我输入数字(运行代码时)它总是给我一个巨大的数字(比如至少 20 个数字)

有没有办法限制数量，还是我做错了什么？

Answer 1

你在这里遗漏了一些括号:

float average = score1+score2+score3+score4+score5+score6+score7+score8+score9+score10/10;

将此更改为:

float average = (score1+score2+score3+score4+score5+score6+score7+score8+score9+score10)/10;

您还需要将此行向下移动，使其出现在输入阶段之后(即在对 scanf 的所有调用之后)，因为尝试没有意义并在您拥有所有输入值之前计算一些东西。

---

您可能想阅读运算符优先级和循环，因为您的程序可以写得更简单和简洁:

#include <stdio.h>

int main()
{
    const int n = 10;
    float sum = 0.0f;
    float average;
    int i;

    printf("Please input the scores of the students: \n");

    for (i = 0; i < n; ++i)
    {
        float score;

        scanf(" %f", &score);
        sum += score;
    }

    average = sum / n;

    printf("The average score is: %.2f" , average);

    return 0;
}