帶有浮點函數的C ++錯誤4716

Question

我在使用float函數的返回值時遇到困難。 每次嘗試輸入返回值時，都會不斷得到錯誤未知值，否則您必須輸入返回值。 我很失落。

這是我的程序：

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

using namespace std;

string studFirstName;
string studLastName;
float studExam1;
float studExam2;
float studExam3;
float studScore;
float studAvg;

void getStudName(string& studFirstName, string& studLastName);
void getStudExams(float& studExam1, float& studExam2, float& studExam3);
float calStudAvg(float studExam1, float studExam2, float studExam3);
void displayGrade(string studFirstName, string studLastName, float studavg);

int main ()
{
    cout << "Enter Student's First Name:";
    cin >> studFirstName;
    cout << endl;

    cout << "Enter Student's Last Name:";
    cin >> studLastName;
    cout << endl;
}

void getStudExams(float& studExam1, float& studExam2, float& studExam3)
{    
    cout << "Enter score for Exam 1:";
    cin >> studExam1;
    cout << endl;

    cout << "Enter score for Exam 2:";
    cin >> studExam2;
    cout << endl;

    cout << "Enter score for Exam 3:";
    cin >> studExam3;
    cout << endl;
}

float calStudAvg(float studExam1, float studExam2, float studExam3)
{
    float studScore = (studExam1 + studExam2 + studExam3);
    float studAvg = (studScore/3);
    return; 
}

void displayGrade(string studFirstName, string studLastName, float studAvg)
{    
    cout << "Student's First Name:";
    getline (cin, studFirstName);
    cout << endl;

    cout << "Student's Last Name:";
    getline (cin, studLastName);
    cout << endl;

    cout << left << "Student's Final Grade:"
    << right << studAvg << endl;

    if (studAvg >= 90)
        cout << "Grade = 'A'" << endl;
    else if (studAvg >= 80)
        cout << "Grade = 'B'" << endl;
    else if (studAvg >= 70)
        cout << "Grade = 'C'" << endl;
    else if (studAvg >= 60)
        cout << "Grade = 'D'" << endl;
    else
        cout << "Grade = 'F'" << endl;

    system("pause");
}

如果有人有任何想法，我真的需要幫助！ 謝謝

Answer 1

float calStudAvg(float studExam1, float studExam2, float studExam3)

{
float studScore = (studExam1 + studExam2 + studExam3);

float studAvg = (studScore/3);

return; 
}

只需將return放入功能塊中就不會返回任何內容。 您必須明確指定希望該函數返回的值。 就像您的情況一樣，您似乎想要執行以下操作：-

return studAvg ;

除此之外，空返回值還指示編譯器將控制權返回給調用者，這意味着即使在返回類型為void的函數中也可以使用空返回。

另外，從數學角度來看，請確保您要計算的平均分數是從相同的數字中計算出來的。 否則，您必須使用加權平均。

Answer 2

我不確切地知道您在找什么，問題是您在哪里調用了這些方法？無論如何嘗試此操作不會顯示任何錯誤，而且您的代碼系統（“暫停”）很慢。 它取決於平台。 這是不安全的。 所以請使用其他方法

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

using namespace std;

string studFirstName;
string studLastName;
float studExam1;
float studExam2;
float studExam3;
float studScore;
float studAvg;

void getStudName(string& studFirstName, string& studLastName);
void getStudExams(float& studExam1, float& studExam2, float& studExam3);
float calStudAvg(float studExam1, float studExam2, float studExam3);
void displayGrade(string studFirstName, string studLastName, float studavg);

int main ()
{

cout << "Enter Student's First Name:";
cin >> studFirstName;
cout << endl;

cout << "Enter Student's Last Name:";
cin >> studLastName;
cout << endl;
}

void getStudExams(float& studExam1, float& studExam2, float& studExam3)

{   

cout << "Enter score for Exam 1:";
cin >> studExam1;
cout << endl;

cout << "Enter score for Exam 2:";
cin >> studExam2;
cout << endl;

cout << "Enter score for Exam 3:";
cin >> studExam3;
cout << endl;
}

float calStudAvg(float studExam1, float studExam2, float studExam3)

{
float studScore = (studExam1 + studExam2 + studExam3);

float studAvg = (studScore/3);

return studAvg; 
}

void displayGrade(string studFirstName, string studLastName, float studAvg)

{   
cout << "Student's First Name:";
getline (cin, studFirstName);
cout << endl;

cout << "Student's Last Name:";
getline (cin, studLastName);
cout << endl;

cout << left << "Student's Final Grade:"
<< right << studAvg << endl;

if (studAvg >= 90)
    cout << "Grade = 'A'" << endl;
else if (studAvg >= 80)
    cout << "Grade = 'B'" << endl;
else if (studAvg >= 70)
    cout << "Grade = 'C'" << endl;
else if (studAvg >= 60)
    cout << "Grade = 'D'" << endl;
else
    cout << "Grade = 'F'" << endl;

}