（注意：这是问题的更新版本） 所以我正在升级我以前工作过的项目。 现在，它将程序的输出打印到文件，以及组织成绩。 到目前为止，一切都应该正常，除了一个错误。 这是代码：
#include <iostream>
#include <string>
#include <fstream>
using namespace std;
struct Classes
{
double acousticGuitarEnsemble;
double biology;
double english;
double geometry;
double hebrew;
double jewishStudies;
double worldHistory;
};
void grade1(Classes eitan)
{
newGrade1:
cout << "Which grade are you entering? (Use the following format: exampleFormat): ";
string classBeingEntered1;
cin >> classBeingEntered1;
cout << "Enter the new grade: ";
double grade1;
cin >> grade1;
cout << "Grade entered." << endl;
if (classBeingEntered1 == "acousticGuitarEnsemble")
eitan.acousticGuitarEnsemble = grade1;
else if (classBeingEntered1 == "biology")
eitan.biology = grade1;
else if (classBeingEntered1 == "english")
eitan.english = grade1;
else if (classBeingEntered1 == "jewishStudies")
eitan.jewishStudies = grade1;
else if (classBeingEntered1 == "geometry")
eitan.geometry = grade1;
else if (classBeingEntered1 == "hebrew")
eitan.hebrew = grade1;
else if (classBeingEntered1 == "worldHistory")
eitan.worldHistory = grade1;
else
cout << "Invalid class name. Try again." << endl;
goto newGrade1;
}
void grade2(Classes eitan)
{
newGrade2:
cout << "Which grade are you entering? (Use the following format: exampleFormat): ";
string classBeingEntered2;
cin >> classBeingEntered2;
cout << "Enter the new grade: ";
double grade2;
cin >> grade2;
cout << "Grade entered." << endl;
if (classBeingEntered2 == "acousticGuitarEnsemble")
eitan.acousticGuitarEnsemble = grade2;
else if (classBeingEntered2 == "biology")
eitan.biology = grade2;
else if (classBeingEntered2 == "english")
eitan.english = grade2;
else if (classBeingEntered2 == "jewishStudies")
eitan.jewishStudies = grade2;
else if (classBeingEntered2 == "geometry")
eitan.geometry = grade2;
else if (classBeingEntered2 == "hebrew")
eitan.hebrew = grade2;
else if (classBeingEntered2 == "worldHistory")
eitan.worldHistory = grade2;
else
cout << "Invalid class name. Try again." << endl;
goto newGrade2;
}
void grade3(Classes eitan)
{
newGrade3:
cout << "Which grade are you entering? (Use the following format: exampleFormat): ";
string classBeingEntered3;
cin >> classBeingEntered3;
cout << "Enter the new grade: ";
double grade3;
cin >> grade3;
cout << "Grade entered." << endl;
if (classBeingEntered3 == "acousticGuitarEnsemble")
eitan.acousticGuitarEnsemble = grade3;
else if (classBeingEntered3 == "biology")
eitan.biology = grade3;
else if (classBeingEntered3 == "english")
eitan.english = grade3;
else if (classBeingEntered3 == "jewishStudies")
eitan.jewishStudies = grade3;
else if (classBeingEntered3 == "geometry")
eitan.geometry = grade3;
else if (classBeingEntered3 == "hebrew")
eitan.hebrew = grade3;
else if (classBeingEntered3 == "worldHistory")
eitan.worldHistory = grade3;
else
cout << "Invalid class name. Try again." << endl;
goto newGrade3;
}
void grade4(Classes eitan)
{
newGrade4:
cout << "Which grade are you entering? (Use the following format: exampleFormat): ";
string classBeingEntered4;
cin >> classBeingEntered4;
cout << "Enter the new grade: ";
double grade4;
cin >> grade4;
cout << "Grade entered." << endl;
if (classBeingEntered4 == "acousticGuitarEnsemble")
eitan.acousticGuitarEnsemble = grade4;
else if (classBeingEntered4 == "biology")
eitan.biology = grade4;
else if (classBeingEntered4 == "english")
eitan.english = grade4;
else if (classBeingEntered4 == "jewishStudies")
eitan.jewishStudies = grade4;
else if (classBeingEntered4 == "geometry")
eitan.geometry = grade4;
else if (classBeingEntered4 == "hebrew")
eitan.hebrew = grade4;
else if (classBeingEntered4 == "worldHistory")
eitan.worldHistory = grade4;
else
cout << "Invalid class name. Try again." << endl;
goto newGrade4;
}
void grade5(Classes eitan)
{
newGrade5:
cout << "Which grade are you entering? (Use the following format: exampleFormat): ";
string classBeingEntered5;
cin >> classBeingEntered5;
cout << "Enter the new grade: ";
double grade5;
cin >> grade5;
cout << "Grade entered." << endl;
if (classBeingEntered5 == "acousticGuitarEnsemble")
eitan.acousticGuitarEnsemble = grade5;
else if (classBeingEntered5 == "biology")
eitan.biology = grade5;
else if (classBeingEntered5 == "english")
eitan.english = grade5;
else if (classBeingEntered5 == "jewishStudies")
eitan.jewishStudies = grade5;
else if (classBeingEntered5 == "geometry")
eitan.geometry = grade5;
else if (classBeingEntered5 == "hebrew")
eitan.hebrew = grade5;
else if (classBeingEntered5 == "worldHistory")
eitan.worldHistory = grade5;
else
cout << "Invalid class name. Try again." << endl;
goto newGrade5;
}
void grade6(Classes eitan)
{
newGrade6:
cout << "Which grade are you entering? (Use the following format: exampleFormat): ";
string classBeingEntered6;
cin >> classBeingEntered6;
cout << "Enter the new grade: ";
double grade6;
cin >> grade6;
cout << "Grade entered." << endl;
if (classBeingEntered6 == "acousticGuitarEnsemble")
eitan.acousticGuitarEnsemble = grade6;
else if (classBeingEntered6 == "biology")
eitan.biology = grade6;
else if (classBeingEntered6 == "english")
eitan.english = grade6;
else if (classBeingEntered6 == "jewishStudies")
eitan.jewishStudies = grade6;
else if (classBeingEntered6 == "geometry")
eitan.geometry = grade6;
else if (classBeingEntered6 == "hebrew")
eitan.hebrew = grade6;
else if (classBeingEntered6 == "worldHistory")
eitan.worldHistory = grade6;
else
cout << "Invalid class name. Try again." << endl;
goto newGrade6;
}
void grade7(Classes eitan)
{
newGrade7:
cout << "Which grade are you entering? (Use the following format: exampleFormat): ";
string classBeingEntered7;
cin >> classBeingEntered7;
cout << "Enter the new grade: ";
double grade7;
cin >> grade7;
cout << "Grade entered." << endl;
if (classBeingEntered7 == "acousticGuitarEnsemble")
eitan.acousticGuitarEnsemble = grade7;
else if (classBeingEntered7 == "biology")
eitan.biology = grade7;
else if (classBeingEntered7 == "english")
eitan.english = grade7;
else if (classBeingEntered7 == "jewishStudies")
eitan.jewishStudies = grade7;
else if (classBeingEntered7 == "geometry")
eitan.geometry = grade7;
else if (classBeingEntered7 == "hebrew")
eitan.hebrew = grade7;
else if (classBeingEntered7 == "worldHistory")
eitan.worldHistory = grade7;
else
cout << "Invalid class name. Try again." << endl;
goto newGrade7;
}
Classes gradeEditor(Classes eitan)
{
cout << "GradeBook 1.2" << endl;
grade1(eitan);
cout << "Editing next grade..." << endl;
grade2(eitan);
cout << "Editing next grade..." << endl;
grade3(eitan);
cout << "Editing next grade..." << endl;
grade4(eitan);
cout << "Editing next grade..." << endl;
grade5(eitan);
cout << "Editing next grade..." << endl;
grade6(eitan);
cout << "Entering next grade..." << endl;
grade7(eitan);
return eitan;
}
void choice(Classes eitan)
{
choiceBack:
cout << "Do you want to edit another grade? (If yes, you must reset all the grades) Press Y or N: ";
char chChoice;
cin >> chChoice;
switch (chChoice) {
case 'Y':
cout << "Alright then!" << endl;
do {
gradeEditor(eitan);
goto choiceBack; // Refers to beginning of choice() function
} while (chChoice == 'Y');
case 'N':
cout << "Printing grades..." << endl;
break;
case 'y':
cout << "Alright then!" << endl;
do {
gradeEditor(eitan);
goto choiceBack; // Refers to beginning of choice() function
} while (chChoice == 'y');
case 'n':
cout << "Printing grades..." << endl;
break;
}
}
void printGrades(Classes eitan)
{
cout << "Acoustic Guitar Ensemble: " << eitan.acousticGuitarEnsemble << endl;
cout << "Biology: " << eitan.biology << endl;
cout << "English: " << eitan.english << endl;
cout << "Jewish Studies: " << eitan.jewishStudies << endl;
cout << "Geometry: " << eitan.geometry << endl;
cout << "Hebrew: " << eitan.hebrew << endl;
cout << "World History: " << eitan.worldHistory << endl;
system("PAUSE");
}
int main(Classes eitan)
{
ofstream outputFile;
outputFile.open("userGrades.txt");
gradeEditor(eitan);
choice(eitan);
printGrades(eitan);
outputFile.close();
cout << "Grades saved to file!" << endl;
return 0;
}
在课程gradeEditor（）中，我正在进入7年级。 但是，7次后它不会停止。 有人看到如何解决这个问题？ - 艾坦 P.S：我知道人们在使用goto时遇到了问题。但我还没有找到一种方法，可以在那里使用一段时间来处理这些具体情况。除非你能告诉我一个更好的替代品，否则不要提及它。 P.P.S：此时，我并不清楚如何更好地格式化我的程序。我确实理解编程语法，但我现在这样做。
答案 0 :(得分：1)
错误消息非常清楚。问题不在于return关键字。问题是尝试使用变量而不初始化它。
Classes eitan;
//several lines of code in which you do nothing with eitan, then:
return eitan;
如果您尝试执行return以外的其他操作，则会遇到相同的错误消息。
如果您需要使用eitan中声明的main，请将其作为变量传递。
Classes gradeEditor(Classes& c) {
//stuff
return c;
}
并称之为：
gradeEditor(eitan);
对所有void函数执行相同的操作。
如果您不想传递变量，但想在多个函数中使用它，则必须将其声明为全局变量。简单地创建一个恰好在不同范围内具有相同名称的新变量不会使这两个变量指向相同的信息。
你陷入了无限循环，因为：
else
cout << "Invalid class name. Try again." << endl;
goto newGrade2;
不符合您的想法。你需要花括号：
else {
cout << "Invalid class name. Try again." << endl;
goto newGrade2;
}
答案 1 :(得分：0)
你应该重写你的代码并删除所有goto，它被认为是 糟糕的做法 - 至少在你正在做的那种程序中。
您可以像这样重写choice函数，另请注意
Classes通过引用传递，允许它进行修改。通过它
通过引用你可以修改它，这是你应该做的
在修改它的所有函数中执行，否则更改将执行
因为您将副本传递给函数
#include <cctype> // for std::toupper
void choice(Classes& eitan) // pass by reference to modify argument
{
do
{
cout << "Do you want to edit another grade? (If yes, you must reset all the grades) Press Y or N: ";
char chChoice;
cin >> chChoice;
chChoice = std::toupper(chChoice);
switch (chChoice)
{
case 'Y':
cout << "Alright then!" << endl;
gradeEditor(eitan);
break;
case 'N':
cout << "Printing grades..." << endl;
break;
default:
cout << "Please answer Y or N!" << endl;
break;
}
}
while ( chChoice != 'N' );
}