成绩不会显示

这对我来说很有效。

 class EssayClass{
     //private fields to hold data
     private:
     //Member names are best(In my opinion) given as: m_typeName. IE:double m_dblGrammar;
          double Grammar;
          double Spelling;
          double CL;
          double Content;
          double score;
          string grade;
     //public methods for outside code
     public:
          EssayClass(double G, double S, double corlen, double content, double Score, string &Grade){
         Grammar = G;
         Spelling = S;
         CL = corlen;
         Content = content;
         score = Score;
         //Set this here instead of in the private section as this is not a static variable.
         grade= "";
     }//end EssayClass constructor
//method to add score
//NOTE: You do not use the parameter; thus was omitted.
     void addScore(){
         score = Grammar + Spelling + CL + Content;
     }// end add score
//method to show final grade
     void findGrade(){
          //Another thing I'm fond of, which helps prevent typo's
         //Is to have your constant be a left hand compare. For example
        //if(5 == foo). Help you prevent from accidental if(foo = 5)'s
         if (score >= 95)
              grade = "A";
         else if (score >= 79)
              grade = "B";
         else if (score >= 50)
              grade = "C";
         else //this should probably be just "else"
              grade = "F";
     }//end findGrade
     double getGrammar(){
         return Grammar;
     }//end getGrammar
     double getSpelling(){
         return Spelling;
     }//end getSpelling
     double getCL(){
         return CL;
     }
      double getContent(){
              return Content;
          }//end getContent
      double getScore(){
             return score;
         }//end getScore
      string &getGrade(){
        return grade;
    }//end getGrade
};//end class

和：

void userInput(double &grammar, double &spelling, double &CL, double &content);
int main ()
{
    //some variables, good habit is to set these to 0, although that's probably just 'C' Mentality that I haven't gotten rid of
    double grmmr = 0.0;
    double splling = 0.0;
    double correctlength = 0.0;
    double con = 0.0;
    double scr = 0.0;
    std::string grde = "";
    //Note: 4 parameters in declaration, 4 in useage.
    userInput(grmmr, splling, correctlength, con);
    //displaying the scores that were inputed
    cout << "The recorded scores are:" << endl;
    cout << "Grammar: " << grmmr << endl;
    cout << "Spelling: " << splling << endl;
    cout << "Correct Length: " << correctlength << endl;
    cout << "Content: " << con << endl;
    EssayClass essayObject(grmmr, splling, correctlength, con, scr, grde);
    //calling member functions with essay object
    userInput(grmmr, splling, correctlength, con);
    essayObject.addScore();
    essayObject.findGrade();
    essayObject.getGrade();
    //NOTE: There is no string grde here, as I declared it above.
    grde = essayObject.getGrade();

    //final grade
    cout << "The grade for this essay is: " << grde << endl;
    //generally bad practice to use system calls -- however for homework it has it's purpose.
    system("Pause");
    return 0;
}//end main
void userInput(double &grmmr, double &splling, double &correctlenght, double &con)
{
    //input from user to enter points
    cout << "Enter the points for an essay." << endl;
    cout << "Grammar (must be 30 or less points)." << endl;
    cin >> grmmr;
    while (grmmr > 30 || grmmr < NUM_FOR_CAL1)
    {
        cout << "Grammar must be 30 or less points." << endl;
        cin >> grmmr;
    }//end while loop
    cout << "Spelling (must be 20 or less points)." << endl;
    cin >> splling;
    while(splling > 20 || splling < NUM_FOR_CAL1)
    {
        cout << "Spelling must be 20 or less points." << endl;
        cin>> splling;
    }//end while loop
    cout << "Correct length (must be 20 or less points)." << endl;
    cin>> correctlenght;
    while(correctlenght > 20 || correctlenght < NUM_FOR_CAL1)
    {
        cout << "Correct length must be 20 or less points." << endl;
        cin >> correctlenght;
    }//end while loop
    cout << "Correct content (must be 30 or less points)." << endl;
    cin>> con;
    while( con > 30 || con < NUM_FOR_CAL1)
    {
        cout << "Content must be 30 or less points." << endl;
        cin >> con;
    }//end while loop
}// end user input**

几件事：

string grade=" ";

在C++中无法做到这一点。不能像这样初始化成员。修复它！

EssayClass(double G, double S, double corlen, double content, double Score, string Grade)

所以EssayClass构造函数需要5个双精度和一个字符串。好的。

EssayClass essayObject(grmmr, splling, correctlength, con, scr, grde);

您用4个双精度、一个"scr"（没有这样的变量）和一个双精度调用EssayClass构造函数。这不是它所接受的。修复它！

顺便说一句，不要以大写字母开头变量！这被认为是一种糟糕的风格。大写字母表示宏、类名和其他类型名，有时也表示函数（包括成员函数）。

另一方面，所有getSomething函数都应该是常量，getGrade（）应该返回const string&，而不是string。类似地，构造函数应该接收const string&，而不是string。从形式上讲，这不是一个错误，但这种参数传递会导致代码效率低下。

您应该始终在"="前后留出一个空格，否则您的代码将很难阅读。

您的代码有更多的问题，但首先，修复这些问题。

侧面评论：

1. 避免在头文件中使用"namespacestd；"，因为包括它在内的所有文件都将继承它
2. 如果等级总是一个字符，则可以使用char
3. 如果计算了等级，则不需要在构造函数中传递，而是可以在构造函数中计算