错误:候选构造函数不可行:需要5个参数，但提供了0

Question

我的项目有问题。它一直说构造函数有问题，但我找不到问题。对于代码的长度，我很抱歉，我肯定我错过了一些愚蠢的东西。

原谅我的标题..。DateTime.h

    using namespace std;

//Constant array containing the days in the given month
const int DAYS_OF_MONTH[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

//Custom Date/Time format with a year that 1/1 is a sunday (Ex. 2017) to make things simpler
class DateTime {
  int month, day, hour, minute;

  public:
  //Creates a basic blank DateTime
  DateTime() {
    month = 1;
    day = 1;
    hour = 0;
    minute = 0;
  }

  //Creates a DateTime with a specific Date and Time
  DateTime(int m, int d, int h, int min) {
    month = m;
    day = d;
    hour = h;
    minute = min;
  }

  //Adds the days to the date and updates the month if the day goes over
  void addDays(int d) {
    try {
    for(int i = 0; i < d; i++) {
      day++;
      if(day > DAYS_OF_MONTH[month-1]) {
        month++;
        day = 1;
      }
    }
    }
    catch(string ex) {

    }
  }

  //Adds a week onto the Date
  void addWeeks(int w) {
    for(int i = 0; i < w; i++) {
      addDays(7);
    }
  }

  //Accessors
  int getMonth() {
    return month;
  }
  int getDay() {
    return day;
  }
  int getHour() {
    return hour;
  }
  int getMinute() {
    return minute;
  }

  //Mutators
  void setMonth(int newM) {
    month = newM;
  }
  void setDay(int newD) {
    day = newD;
  }
  void setHour(int newH) {
    hour = newH;
  }
  void setMinute(int newM) {
    minute = newM;
  }
};`

Day.h

#include<string>
#include "DateTime.h"

class Day {
  DateTime startTime;
  DateTime endTime;
  int weekOfYear;
  int dayOfWeek;

  public:
  //Creates a blank day
  Day() {
    startTime = DateTime(1, 1, 0, 0);
    endTime = DateTime(1, 1, 0, 0);
    weekOfYear = 0;
    dayOfWeek = 0;
  }

  //Creates a blank day with a specific date
  Day(int wOfY, int dOfW) {
    startTime = DateTime(1, 1, 0, 0);
    endTime = DateTime(1, 1, 0, 0);
    weekOfYear = wOfY;
    dayOfWeek = dOfW;

    //Add weeks of the year and days of the week to the date
    startTime.addDays(dOfW-1);
    startTime.addWeeks(wOfY-1);
    endTime.addDays(dOfW-1);
    endTime.addWeeks(wOfY-1);
  }

  //Create a filled day with specific date and start/end times
  Day(int wOfY, int dOfW, int startHr, int startMin, int endHr, int endMin) {
    startTime = DateTime(1, 1, startHr, startMin);
    endTime = DateTime(1, 1, endHr, endMin);
    weekOfYear = wOfY;
    dayOfWeek = dOfW;
  }

  //Accessors
  DateTime getStartTime() {
    return startTime;
  }
  DateTime getEndTime() {
    return endTime;
  }
  int getWeekOfYear() {
    return weekOfYear;
  }
  int getDayOfWeek() {
    return dayOfWeek;
  }

  //Mutators
  void setStartTime(DateTime newTime) {
    startTime = newTime;
  }
  void setEndTime(DateTime newTime) {
    endTime = newTime;
  }
  void setWeekOfYear(int newWOfY) {
    weekOfYear = newWOfY;
  }
  void setDayOfWeek(int newDOfW) {
    dayOfWeek = newDOfW;
  }

  //Calculates the amount of time between startTime and endTime
  float getDailyHours() {
    if((float)endTime.getHour() - (float)startTime.getHour() >=1) {
      return ((60- (float)startTime.getMinute())/60) + ((float)endTime.getHour() - (float)startTime.getHour() - 1) + ((float)endTime.getMinute() / 60);
    }
    else {
      return ((float)endTime.getMinute() - (float)startTime.getMinute()) / 60;
    }
  }

  //Returns the data of the day in the format to save to the file
  string toString() {
   return string(",") + to_string(dayOfWeek) + string(",") + to_string(startTime.getHour()) + string(",") + to_string(startTime.getMinute()) + string(",") + to_string(endTime.getHour()) + string(",") + to_string(endTime.getMinute());
  }
};

Week.h

#include "Day.h"
#include <vector>
using namespace std;

class Week {
  vector<Day> dayList;
  float totalWeeklyHours;
  int weekOfYear;

  public:
  //Creates a basic week
  Week(int wOfY) {
    //dayList.resize(7);
    weekOfYear = wOfY;
    
    for(int i = 0; i < 7; i++) {
      dayList.push_back(Day(weekOfYear, i));
    }
  }

  //Creates a week given a dayList
  Week(int wOfY, vector<Day> dL) {
    //dayList.resize(7);
    weekOfYear = wOfY;
    for(int i = 0; i < 7; i++) {
      dayList.push_back(dL.at(i));
    }
  }

  //Accessors
  int getWeekOfYear() {
    return weekOfYear;
  }
  vector<Day> getDayList() {
    return dayList;
  }

  //Adds a day to dayList from EmployeeManager.readFile()
  void addDay(int wOfY, int dOfW, int startHr, int startMin, int endHr, int endMin) {
    Day temp = Day(wOfY, dOfW, startHr, startMin, endHr, endMin);
    dayList.at(dOfW) = temp;
    weekOfYear = temp.getWeekOfYear();
  }

  //Adds a day from Employee.addWeek()
  void addDay(Day newDay, int dOfW) {
    dayList.at(dOfW) = newDay;
    weekOfYear = newDay.getWeekOfYear();
  }

  //Calculates the total amount of hours scheduled in the week
  float getTotalWeeklyHours() {
    totalWeeklyHours = 0;
    for(int i = 0; i < dayList.size(); i++) {
      totalWeeklyHours += dayList.at(i).getDailyHours();
    }

    return totalWeeklyHours;
  }

  //Returns the data of the week in the format to save in the file
  string toString() {
    return (string)"," + to_string(weekOfYear) + dayList.at(0).toString() + dayList.at(1).toString() + dayList.at(2).toString() + dayList.at(3).toString() + dayList.at(4).toString() + dayList.at(5).toString() + dayList.at(6).toString();
  }
};

Person.h

#include <string>
using namespace std;

class Person {
  public:
    string firstName;
    string lastName;
    int employeeID;
    int employeePIN;
    float hourlyRateOfPay;

  public:
    Person() {
      firstName = "John";
      lastName = "Doe";
      employeeID = 0;
      employeePIN = 0;
      hourlyRateOfPay = 0;
    }

    //Accessors
    string getFirstName() {
      return firstName;
    }
    string getLastName() {
      return lastName;
    }
    int getEmployeeID() {
      return employeeID;
    }
    int getEmployeePIN() {
      return employeePIN;
    }
    float getHourlyRateOfPay() {
      return hourlyRateOfPay;
    }

    //Mutators
    void setFirstname(string newName) {
      firstName = newName;
    }
    void setLastName(string newName) {
      lastName = newName;
    }
    void setEmployeeID(int newID) {
      employeeID = newID;
    }
    void setEmployeePIN(int newPIN) {
      employeePIN = newPIN;
    }
    void setHourlyRateOfPay(float newPay) {
      hourlyRateOfPay = newPay;
    }

    //Abstract methods
    string viewSchedule(int wOfY);
    float viewPay(int wOfY);
};

Employee.h

#include "Person.h"
#include "Week.h"
using namespace std;

class Employee : public Person {
  vector<Week> weekList;

  public:
    Employee(int empID, int empPIN, string fName, string lName, float hROP) {
      employeeID = empID;
      employeePIN = empPIN;
      firstName = fName;
      lastName = lName;
      hourlyRateOfPay = hROP;
      
      /*
      setEmployeeID(empID);
      setEmployeePIN(empPIN);
      setFirstName(fname);
      setLastName(lname);
      setHourlyRateOfPay(hROP);
      */

      for(int i = 0; i < 52; i++) {
        weekList.push_back(Week(i));
      }
    }

    Week getWeek(int wOfY) {
      return weekList.at(wOfY);
    }

    //Adds a week to the weekList from EmployeeManager.readFile()
    void addWeek(int wOfY, vector<Day> dL) {
      for(int i = 0; i < 7; i++) {
        weekList.at(wOfY).addDay(dL.at(i), i);
      }
    }

    //Adds a week from client
    void addWeek(int wOfY, Week newWeek) {
      weekList.at(wOfY) = newWeek;
    }

    //Returns a specified wek to be viewed by the user
    string viewSchedule(int wOfY) {
      return weekList.at(wOfY).toString();
    }

    //Returns the amount of pay for a specified week to be viewed by the user
    float viewPay(int wOfY) {
      return hourlyRateOfPay * (weekList.at(wOfY).getTotalWeeklyHours());
    }

    //Returns the data of the employee in the format to save to the readFile
    string toString() {
      return firstName + "," + lastName + "," + to_string(employeeID) + "," + to_string(employeePIN) + "," + to_string(hourlyRateOfPay);
    }
};

EmployeeManager.h

#include "Employee.h"
#include <fstream>
#include <sstream>
using namespace std;

class EmployeeManager {
  vector<Employee> employeeList;

  public:
  EmployeeManager() {
    //readFile();
  }

  void readFile() {
  //Variables
  int empID, empPIN, wOfY, dOfW, startHr, startMin, endHr, endMin;
  float hROP;
  string fname, lname;

  ifstream input;
  input.open("EmployeeList.csv");
  while(!input.eof()) {
    input >> fname >> lname >> empID >> empPIN >> hROP;

    //Create temp Employee
    Employee tempEmployee = Employee(empID, empPIN, fname, lname, hROP);

    for(int i = 0; i < 52; i++) {
      Week tempWeek = Week(i);
      input >> wOfY;
      for(int j = 0; j < 7; j++) {
        input >> dOfW >> startHr >> startMin >> endHr >> endMin;
        tempWeek.addDay(wOfY, dOfW, startHr, startMin, endHr, endMin);
      }
      tempEmployee.addWeek(wOfY, tempWeek.getDayList());
    }
    addEmployee(tempEmployee);
  }
  input.close();
  }

  void saveFile() {
    ofstream output("EmployeeList.csv");

    for(int i = 0; i < employeeList.size(); i++) {
      output << employeeList.at(i).toString();
      for(int j = 0; j < 52; j++) {
        output << employeeList.at(i).viewSchedule(j);
      }
      output << "\n";
    }
    output.close();
  }

  //Adds a new employee to the employeeList from readFile
  void addEmployee(Employee newEmp) {
    //employeeList.resize(employeeList.size()*2);
    try{
      employeeList.push_back(newEmp);
    }
    catch(out_of_range ex) {
      cout << "EmployeeList out_of_range" << endl;
      int newSize = employeeList.size() * 2;
      employeeList.resize(newSize);
      addEmployee(newEmp);
    }
    
  }

  //Adds a new employee to the employeeList from client
  void addEmployee(int empID, int empPIN, string fname, string lname, float hROP) {
    Employee newEmp = Employee(empID, empPIN, fname, lname, hROP);
    //employeeList.resize(employeeList.size()*2);
    try {
      employeeList.push_back(newEmp);
    }
    catch(out_of_range ex) {
      cout << "EmployeeList out_of_range" << endl;
      int newSize = employeeList.size() * 2;
      employeeList.resize(newSize);
      addEmployee(newEmp);
    }
  }

  bool validateLogin(int empID, int empPIN) {
    for(int i = 0; i < employeeList.size(); i++) {
      if(employeeList.at(i).getEmployeeID() == empID) {
        if(employeeList.at(i).getEmployeePIN() == empPIN) {
          return true;
        }
      }
    }
    return false;
  }

  bool isIDAvailable(int empID) {
    for(int i = 0; i < employeeList.size(); i++) {
      if(employeeList.at(i).getEmployeeID() == empID) {
        return false;
      }
    }
    return true;
  }
};

main.cpp

#include <iostream>
#include "EmployeeManager.h"

int main() {
  Day d1 = Day(9,6);
  cout << d1.toString() << endl;

  Week w1 = Week(1);
  cout <<"\n\n" << w1.toString() << endl;
  
  Employee e1 = Employee(12345, 9876, "Test", "Employee", 15.60);
  cout << "\n\n" << e1.toString();
  for(int i = 0; i < 52; i++) {
    cout << e1.viewSchedule(i);
  }
  cout << endl;

  EmployeeManager em1 = EmployeeManager();
  em1.saveFile();
}

然后我有了一个名为.csv的EmployeeList.csv文件

这是我收到的错误信息

 clang++-7 -pthread -std=c++17 -o main main.cpp
In file included from main.cpp:2:
In file included from ./EmployeeManager.h:1:
In file included from ./Employee.h:2:
In file included from ./Week.h:2:
In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/vector:62:
/usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/stl_construct.h:75:38: error: 
      no matching constructor for initialization of 'Employee'
    { ::new(static_cast<void*>(__p)) _T1(std::forward<_Args>(__args)...); }
                                     ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/stl_uninitialized.h:527:8: note: 
      in instantiation of function template specialization
      'std::_Construct<Employee>' requested here
                std::_Construct(std::__addressof(*__cur));
                     ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/stl_uninitialized.h:583:2: note: 
      in instantiation of function template specialization
      'std::__uninitialized_default_n_1<false>::__uninit_default_n<Employee *,
      unsigned long>' requested here
        __uninit_default_n(__first, __n);
        ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/stl_uninitialized.h:645:19: note: 
      in instantiation of function template specialization
      'std::__uninitialized_default_n<Employee *, unsigned long>' requested here
    { return std::__uninitialized_default_n(__first, __n); }
                  ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/vector.tcc:596:8: note: 
      in instantiation of function template specialization
      'std::__uninitialized_default_n_a<Employee *, unsigned long, Employee>'
      requested here
                std::__uninitialized_default_n_a(this->_M_impl._M_finish,
                     ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/stl_vector.h:827:4: note: 
      in instantiation of member function 'std::vector<Employee,
      std::allocator<Employee> >::_M_default_append' requested here
          _M_default_append(__new_size - size());
          ^
./EmployeeManager.h:64:20: note: in instantiation of member function
      'std::vector<Employee, std::allocator<Employee> >::resize' requested here
      employeeList.resize(newSize);
                   ^
./Employee.h:5:7: note: candidate constructor (the implicit copy constructor)
      not viable: requires 1 argument, but 0 were provided
class Employee : public Person {
      ^
./Employee.h:5:7: note: candidate constructor (the implicit move constructor)
      not viable: requires 1 argument, but 0 were provided
./Employee.h:9:5: note: candidate constructor not viable: requires 5 arguments,
      but 0 were provided
    Employee(int empID, int empPIN, string fName, string lName, float hROP) {
    ^
1 error generated.
exit status 1

Answer 1

像employeeList.resize(newSize)在std::vector中的操作需要包含元素的默认构造函数，这在类Employee中是遗漏的。这对于在容器中创建空元素是必要的。

如果由于某种原因无法容纳/负担默认构造函数，只需添加默认构造函数，或者存储指针。