我得到2个错误我无法解决; 1无效使用会员（您是否忘记了＆＃39;＆amp;＆＃39;？）和目标＆＃39; main.o＆＃39;失败

Question

当我编译代码时，我在第47行：

上收到错误

[Error] invalid use of member (did you forget the '&' ?)

我不确定为什么，因为我正在尝试为total_score添加分数。

第二个问题是错误说目标＆＃39; main.o＆＃39;失败。这不在我的代码中，但会显示一个标记为makefile.win的新选项卡

这是我的代码：

#include <iostream>
#include <iomanip>
#include <string>
#include <cmath>

using namespace std;

class Student
{

   public:
      void student_name();
      void quiz_score();
      void total_score();
      void average_score();

   private:
      int the_number_of_quizs;
      int sum_of_scores;
      double score_average;
};

void Student::student_name()
{
   string name;
   cout << "Please enter your name" << endl;
   cin >> name;
   cout << endl;
}

void Student::quiz_score()
{
   cout << "What was your score on the quiz?: " << endl;
   int score;
   cin >> score;
   total_score += score;
   the_number_of_quizs++;
}

void Student:: average_score() 
{ 
   score_average= sum_of_scores/ the_number_of_quizs;
}

void Student:: total_score()
{
   cout << "Total score: " << sum_of_scores << endl;
}

int main ()
{
   Student student1;
   student1.quiz_score();
   student1.student_name();
   student1.total_score();
   student1.average_score();

   return 0;
}

Answer 1

你有void total_score()

total_score 是一个返回void的函数，这就是以下内容无效的原因：

total_score += score;

我怀疑你打算使用：

sum_of_scores += score;

Answer 2

如果我完全理解你的所作所为，那么你的主要问题似乎来自你所拥有的那条线：

total_score += score;

运行它会标记你：

main.cpp:38:9: error: invalid use of member function ‘void Student::total_score()’ (did you forget the ‘()’ ?)
         total_score += score;
         ^~~~~~~~~~~

您似乎想将学生的前一个分数添加到他/她的当前分数中。如果我的假设是正确的，那么我认为total_score不应该是你需要的，你需要sum_of_scores

这应该以下面的代码结束你的新代码：

#include <iostream>
#include <iomanip>
#include <string>
#include <cmath>


using namespace std;

class Student
    {

    public:
    void student_name();
    void quiz_score();
    void total_score();
    void average_score();

    private:
    int the_number_of_quizs;
    int sum_of_scores;
    double score_average;


    };
void Student::student_name()
    {
        string name;
        cout << "Please enter your name" << endl;
        cin >> name;
        cout << endl;
    }

void Student::quiz_score()
    {
        cout << "What was your score on the quiz?: " << endl;
        int score;
        cin >> score;
        sum_of_scores += score; //This is where you're correction is.
        the_number_of_quizs++;



    }

void Student:: average_score() 
    { 
    score_average= sum_of_scores/ the_number_of_quizs;

    }


void Student:: total_score()
    {

        cout << "Total score: " << sum_of_scores << endl;
    }



int main ()
{
    Student student1;
    student1.quiz_score();
    student1.student_name();
    student1.total_score();
    student1.average_score();

    return 0;


}

当你运行它时，你应该能够得到这个：