"Not an allowed type" 在涡轮增压C++

Question

我正在尝试制作一个评分系统。所以我想做的是取 outputgrade 值的 1/3 并将其与 outputgrade2 值的 2/3 相加，我尝试了midterm1=(outputgrade()*1/3)+(outputgrade2*2/3)但收到一个错误，即

不允许的类型

请有人帮我做什么。

#include<iostream.h>
#include<conio.h>
#include<iomanip.h>
double AAO,Quizzes,Project,MajorExam,Midterm;

void inputprelim()
    {
        clrscr();
        gotoxy(3,4);cout<<"Input Prelim Grade";
        gotoxy(1,6);cout<<"Attendance/Ass./Oral: ";cin>>AAO;
        gotoxy(1,7);cout<<"Project: ";cin>>Project;
        gotoxy(1,8);cout<<"Quizzes: ";cin>>Quizzes;
        gotoxy(1,9);cout<<"Major Exam: ";cin>>MajorExam;
        gotoxy(1,11);cout<<"Prelim Grade: ";
    }
int getgrade(double a, double b, double c, double d)
    {
        double result;
        result=(a*0.10)+(b*0.20)+(c*0.30)+(d*0.40);
        cout<<setprecision(1)<<result;
        return result;
    }
void outputgrade()
    {
        getgrade(AAO,Project,Quizzes,MajorExam);
        getch();
    }
void inputmidterm()
    {
        gotoxy(33,4);cout<<"Input Midterm Grade";
        gotoxy(29,6);cout<<"Attendance/Ass./Oral: ";cin>>AAO;
        gotoxy(29,7);cout<<"Project: ";cin>>Project;
        gotoxy(29,8);cout<<"Quizzes: ";cin>>Quizzes;
        gotoxy(29,9);cout<<"Major Exam: ";cin>>MajorExam;
        gotoxy(29,11);cout<<"Temporary Midterm Grade: ";
        gotoxy(29,12);cout<<"Final Midterm Grade: ";
    }
void outputgrade2()
    {
        getgrade(AAO,Project,Quizzes,MajorExam);
        getch();
    }

void main()
    {
    inputprelim();
    gotoxy(15,11);outputgrade();
    inputmidterm();
    gotoxy(54,11);outputgrade2();
    gotoxy(55,11);
    Midterm1=(outputgrade()*1/3)+(outputgrade2()*2/3);
    }

Answer 1

您的函数outputgrade()和outputgrade2()的返回类型为 void 。为了在midterm1=(outputgrade()*1/3)+(outputgrade2*2/3)中使用它们，您需要将它们的返回类型更改为 int/double/float 等。

如果我正确理解了您的代码逻辑，请将两个函数编辑为：

double outputgrade()
    {
        return getgrade(AAO,Project,Quizzes,MajorExam);
    }
double outputgrade2()
{
    return getgrade(AAO,Project,Quizzes,MajorExam);
}

我所做的是将返回类型更改为double，同时这两个函数现在返回getgrade返回的任何值。

Answer 2

outputgrade()和outputgrade2()需要返回一个numeric值才能在计算中使用。

现在他们什么都不return。