Visual Studio编译错误:对委托构造函数的调用应该是唯一的成员初始化式

Question

我有这个程序(下面)，一直给我一些编译器错误在Visual studio。但是当我用GCC运行它时，我没有得到编译错误。我真的很想了解如何调试VS和我有麻烦，因为编译器的错误都指向代码的最后一行。谁能帮我弄清楚错误是什么意思，以及如何修复它们?我也有一个pic的错误，VS给我:

#include <iostream>
#include <vector>
#include <fstream>
#include <string>
using namespace std;
struct Course
{
string Course;
int Credit = 0;
int Score = 0;
int Grade = 0;
};
struct Student
{
int ID = 0;
string Name = "";
// Course arrCourse[maxCourseAmt];
vector <Course>Courses;
};
int isInStudVector(vector<Student>vect, int target)
{
int i = 0;
while (i <= vect.size())
{
if (vect[i].ID == target)
return i;
i++;
}
return -1;
}

int main()
{
fstream inputFile;
string  fileName = "StudentRecords.txt";
string token;
//Student arrStu[9];
vector<Student>Students;
inputFile.open(fileName, ios::in);
if (inputFile.is_open())
{
int index = 0;
int ID;
string Name;
string CourseName;
int Credit;
int Score;
while (!inputFile.eof())
{
inputFile >> ID >> Name >> CourseName >> Credit >> Score;
int ii = isInStudVector(Students, ID);
if (ii == -1) // The student record does not exist
{
Students.push_back(Student());
Students[index].ID = ID;
Students[index].Name = Name;
Students[index].Courses.push_back(Course());
Students[index].Courses[0].Course = CourseName;
Students[index].Courses[0].Credit = Credit;
Students[index].Courses[0].Score = Score;
index++;
}
else /// The student exists
{
/// Add course and score to the existing student record
}
}
inputFile.close();
}
else
cout << "File cannot be opened.";
return 0;
}

Rebuild started...
1>------ Rebuild All started: Project: hw1, Configuration: Debug Win32 ------
1>hw1.cpp
1>C:UsersRobsourcereposhw1hw1hw1.cpp(28,14): warning C4018: '<=': signed/unsigned mismatch
1>C:UsersRobsourcereposhw1hw1hw1.cpp(105,1): error C3511: 'Course': a call to a delegating constructor shall be the only member-initializer
1>C:UsersRobsourcereposhw1hw1hw1.cpp(105,1): message : This diagnostic occurred in the compiler generated function 'Course::Course(Course &&)'
1>C:UsersRobsourcereposhw1hw1hw1.cpp(105,1): error C2664: 'Course::Course(const Course &)': cannot convert argument 1 from 'std::string' to 'const Course &'
1>C:UsersRobsourcereposhw1hw1hw1.cpp(105,1): message : Reason: cannot convert from 'std::string' to 'const Course'
1>C:UsersRobsourcereposhw1hw1hw1.cpp(105,1): message : No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
1>C:UsersRobsourcereposhw1hw1hw1.cpp(13,1): message : see declaration of 'Course::Course'
1>C:UsersRobsourcereposhw1hw1hw1.cpp(105,1): message : This diagnostic occurred in the compiler generated function 'Course::Course(Course &&)'
1>C:UsersRobsourcereposhw1hw1hw1.cpp(105,1): error C2437: 'Credit': has already been initialized
1>C:UsersRobsourcereposhw1hw1hw1.cpp(105,1): message : This diagnostic occurred in the compiler generated function 'Course::Course(Course &&)'
1>C:UsersRobsourcereposhw1hw1hw1.cpp(105,1): error C2437: 'Score': has already been initialized
1>C:UsersRobsourcereposhw1hw1hw1.cpp(105,1): message : This diagnostic occurred in the compiler generated function 'Course::Course(Course &&)'
1>C:UsersRobsourcereposhw1hw1hw1.cpp(105,1): error C2437: 'Grade': has already been initialized
1>C:UsersRobsourcereposhw1hw1hw1.cpp(105,1): message : This diagnostic occurred in the compiler generated function 'Course::Course(Course &&)'
1>Done building project "hw1.vcxproj" -- FAILED.
========== Rebuild All: 0 succeeded, 1 failed, 0 skipped ==========

Answer 1

我怀疑您遇到了编译器错误。GCC和Clang都能正确编译你的代码，但MSVC不能。

但是，修复方法很简单。似乎MSVC不喜欢与类同名的成员。只需将Course更改为Name即可:

struct Course
{
string Name;
int Credit = 0;
int Score = 0;
int Grade = 0;
};

Answer 2

VS不喜欢struct Course中的成员string Course，因为"Course"构造函数的隐式名称。重命名成员名或结构名。