Inherited classes cannot call constructor

Hello, I have an assignment that generally deals with Inherited classes and I'm stuck at a problem where I'm getting an error when I try calling the constructor:

Quote:

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error: cannot call constructor ‘HourlyEmployee::HourlyEmployee’ directly [-fpermissive]
employee = HourlyEmployee::HourlyEmployee(sfirstname, slastname, semployeeId, srate, shours);

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This is my parser class where I get the error. The comments are what I tried already:

Code:

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#include <string>
#include "StaffMember.h"
#include "HourlyEmployee.h"
using namespace std;
#ifndef STAFFMEMBERPARSER_H

#define STAFFMEMBERPARSER_H

class StaffMemberParser
{
 
    public:
    static StaffMember* parseStringToMember(string lineToParse)
    {
    string stype, sfirstname, slastname, semployeeId, srate, shours, sbonus; //I initialize the data here
    int pos, pos2, pos3, pos4, pos5, pos6;                          // because it would give me an error otherwise.
   
        pos = lineToParse.find("/");
        stype = lineToParse.substr(0,pos);
       
        pos2 = lineToParse.find("/", pos+1);
        sfirstname = lineToParse.substr(pos+1,pos2-pos-1);
       
        pos3 = lineToParse.find("/", pos2+1);
        slastname = lineToParse.substr(pos2+1,pos3-pos2-1);
       
        pos4 = lineToParse.find("/", pos3+1);
        semployeeId = lineToParse.substr(pos3+1,pos4-pos3-1);
   
        if(stype == "Volunteer")
        {
        //  Volunteer:Volunteer(sfirstname,slastname, semployeeId);
        }
   
        if(stype == "FullTimeEmployee")
        {
        pos5 = lineToParse.find("/", pos4+1);
        srate = lineToParse.substr(pos4+1,pos5-pos4-1);
     
        pos6 = lineToParse.find("/", pos5+1);
        sbonus = lineToParse.substr(pos5+1,pos6-pos5-1);
       
        }
       
        if(stype == "HourlyEmployee")
        {
        pos5 = lineToParse.find("/", pos4+1);
        srate = lineToParse.substr(pos4+1,pos5-pos4-1);
     
        pos6 = lineToParse.find("/", pos5+1);
        shours = lineToParse.substr(pos5+1,pos6-pos5-1);
       
      //  HourlyEmployee::HourlyEmployee(sfirstname, slastname, semployeeId, srate, shours);
        StaffMember* employee;
      // employee = &(HourlyEmployee(sfirstname, slastname, semployeeId, srate, shours));
        employee =  HourlyEmployee::HourlyEmployee(sfirstname, slastname, semployeeId, srate, shours);  //happens at this line
        //return employee;
        }
    }
};
#endif

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Here is the hourlyemployee class:

Code:

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// Child class
#include "StaffMember.h" //include the parent class header
using namespace std;
#ifndef HOURLYEMPLOYEE_H

#define HOURLYEMPLOYEE_H

class HourlyEmployee : public StaffMember
{
   
private:
double rate;
int hoursWorked;

public:

HourlyEmployee(string firstName, string lastName, string memberId, double newRate, int newHoursWorked) : StaffMember(firstName, lastName, memberId)
{
   
    rate = newRate;
    hoursWorked = newHoursWorked;
}

void computePay()
{
    pay = rate*hoursWorked;
}

//overriding the printInfo function from the parent class
virtual void printInfo()
{
cout << "\nHourly Employee:";
StaffMember:printInfo();
cout << "Rate:\t\t\t$" << rate << endl;
cout << "Hours:\t\t\t$" << hoursWorked << endl;
}
};
#endif

---

Staffmember class:

Code:

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#include <string>
using namespace std;
#ifndef STAFFMEMBER_H

#define STAFFMEMBER_H

class StaffMember
{
    protected:
    string firstName;
    string lastName;
    string memberID;
    double pay = 0.0;
   
    public:
    StaffMember(string newfirstName, string newlastName , string newmemberID)
    {
        firstName = newfirstName;
        lastName = newlastName;
        memberID = newmemberID;
        pay = 0.0;
    }
   
    string getMemberId()
    {
        return memberID;
    }

    virtual void computePay() = 0;
   
    virtual void printInfo()
    {
        cout << "\nFirst name:\t\t" << firstName << endl;
        cout << "Last name:\t\t" << lastName << endl;
        cout << "Member ID:\t\t" << memberID << endl;
        cout << "Pay:\t\t\t$" << pay << endl;
    }
   
};
#endif

---

Main class:

Code:

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// Assignment #: 7
//        Name:
// EmailAddress:
//  Description: It displays a menu of choices
//              (add volunteers, full time employees, or hourly employees,
//              compute their pay, search a member, list members,
//              quit, display menu) to a user.
//              Then it performs the chosen task. It will keep asking a user to
//              enter the next choice until the choice of 'Q' (Quit) is
//              entered.

#include <iostream>
#include <string>
#include <cstdlib>
#include <vector>
#include "StaffMember.h"
#include "StaffMemberParser.h"

using namespace std;

void printMenu();


int main()
{
    char input1;
    string inputInfo;
    bool operation;

    vector<StaffMember *> memberList;


    printMenu();    // print out menu


    do
    {
        cout << "What action would you like to perform?" << endl;
        cin >> input1;

        switch (input1)
        {
        case 'A':  //Add Member
            cout << "Please enter a member information to add:\n";
            cin >> inputInfo;
  /***********************************************************************************
  ADD your code here to create a pointer to an object of one of child classes of
  StaffMember class and add it to the memberList
  ***********************************************************************************/
            StaffMemberParser::parseStringToMember(inputInfo);
 
            break;
        case 'C':  //Compute Pay
  /***********************************************************************************
  ***  ADD your code here to compute the pay for all members the memberList.
  ***********************************************************************************/
            for (int j=0; j < memberList.size(); j++)
            {
                memberList.at(j)->computePay();
            }
           
            cout << "pay computed\n";
            break;
        case 'D':  //Search for Member
            cout << "Please enter a memberID to search:\n";
            cin >> inputInfo;
            operation = false;
  /***********************************************************************************
  ***  ADD your code here to search a given memberID. If found, set "found" true,
  ***  and set "found" false otherwise.
  ***********************************************************************************/
            for (int j=0; j < memberList.size(); j++)
            {
                if (inputInfo == memberList.at(j)->getMemberId())
                {
                      operation = true;
                }
                else
                {
                      operation = false;
                }
            }
       
            if (operation == true)
                cout << "member found\n";
            else
                cout << "member not found\n";
            break;
        case 'L':  //List Members
  /***********************************************************************************
  ***  ADD your code here to print out all member objects. If there is no member,
  ***  print "no member\n"
  ***********************************************************************************/
            if (sizeof(memberList) == 0)
            {
                cout << "no member\n" << endl;
            }
            else
            {
                cout << "there are members" << endl;

                for (int j=0; j < memberList.size(); j++)
                {
                    memberList.at(j)->printInfo();
                } 
            }
           
            break;
        case 'Q':  //Quit
            for (int j=0; j < memberList.size(); j++)
            {
                delete memberList.at(j);
            }
            break;
        case '?':  //Display Menu
            printMenu();
            break;
        default:
            cout << "Unknown action\n"  <<endl;
            break;
        }

    } while (input1 != 'Q' && input1 != 'q'); // stop the loop when Q is read

}

/** The method printMenu displays the menu to a user **/
void printMenu()
{
    cout << "Choice\t\tAction\n";
    cout << "------\t\t------\n";
    cout << "A\t\tAdd Member\n";
    cout << "C\t\tCompute Pay\n";
    cout << "D\t\tSearch for Member\n";
    cout << "L\t\tList Members\n";
    cout << "Q\t\tQuit\n";
    cout << "?\t\tDisplay Help\n\n";
}

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Remove the "HourlyEmployee::" and it should work. Remember, you don't call the constructor, you create an object. The object, upon its creation, calls the constructor.

Still though, that would be wrong too, because "employee" is a pointer. I don't know what you're trying to do, but if you want to assign a new object to employee you should delete the old object and make a new one.

The error message seems pretty clear: cannot call constructor ‘HourlyEmployee::HourlyEmployee’ directly

That is, you should have written:

Code:

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HourlyEmployee(sfirstname, slastname, semployeeId, srate, shours);

---

instead of:

Code:

---

HourlyEmployee::HourlyEmployee(sfirstname, slastname, semployeeId, srate, shours);

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However, this does not solve the problem entirely: you may create an object, but the destination is a pointer. Hence, you would need to write something like this:

Code:

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StaffMember* employee = new HourlyEmployee(sfirstname, slastname, semployeeId, srate, shours);

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Unfortunately, doing this means that you now have to do manual memory management, which increases the chance of bugs. Therefore, I would recommend that you #include <memory> and use a unique_ptr instead:

Code:

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std::unique_ptr<StaffMember> employee = std::make_unique<HourlyEmployee>(sfirstname, slastname, semployeeId, srate, shours);

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Now, you can use employee just as you would a StaffMember*, and it would point to an HourlyEmployee, hence allowing the use of polymorphism. At the same time, you don't have to worry about manual memory management as the HourlyEmployee object would be destroyed when the employee unique_ptr goes out of scope before transferring ownership.

EDIT:
This does mean that you need to change the return type of parseStringToMember to be a std::unique_ptr<StaffMember>, but unique_ptrs are designed to be cheap to return, so there's no concern. Furthermore, since it looks like your intent is to return the pointer immediately, there's no need to actually have a pointer variable. You could simplify to:

Code:

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return std::make_unique<HourlyEmployee>(sfirstname, slastname, semployeeId, srate, shours);

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Also, since StaffMember is a polymorphic base class, you should declare its destructor to be virtual, otherwise attempting to destroy an HourlyEmployee through a StaffMember pointer will result in undefined behaviour.

Quote:

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Originally Posted by GReaper

Remove the "HourlyEmployee::" and it should work. Remember, you don't call the constructor, you create an object. The object, upon its creation, calls the constructor.

Still though, that would be wrong too, because "employee" is a pointer. I don't know what you're trying to do, but if you want to assign a new object to employee you should delete the old object and make a new one.

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When I tried to remove the "HourlyEmployee::" ,it gave me another error:

Quote:

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StaffMemberParser.h: In static member function ‘static StaffMember* StaffMemberParser::parseStringToMember(std::string )’:
StaffMemberParser.h:56:85: error: no matching function for call to ‘HourlyEmployee::HourlyEmployee(std::string&, std::string&, std::string&, std::string&, std::string&)’
employee = HourlyEmployee(sfirstname, slastname, semployeeId, srate, shours);

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The employee pointer is only a temporary and it returns the values that I passed on.

Quote:

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Originally Posted by laserlight

The error message seems pretty clear: cannot call constructor ‘HourlyEmployee::HourlyEmployee’ directly

That is, you should have written:
However, this does not solve the problem entirely: you may create an object, but the destination is a pointer. Hence, you would need to write something like this:

Code:

---

StaffMember* employee = new HourlyEmployee(sfirstname, slastname, semployeeId, srate, shours);

---

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Unfortunately I am getting the same error as I described above when I try to change it.

That error message is a little less obvious, but what "no matching function for call" means is that you either have a typo with the function name (unlikely since this is the class name), or your argument list for the function call does not match the parameter list. As it turns out, it is the latter: the last two parameters of the constructor are double and int respectively, but you're passing string arguments. You need to convert those strings to double and int appropriately, e.g., with std::stod and std::stoi.

Quote:

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Originally Posted by laserlight

That error message is a little less obvious, but what "no matching function for call" means is that you either have a typo with the function name (unlikely since this is the class name), or your argument list for the function call does not match the parameter list. As it turns out, it is the latter: the last two parameters of the constructor are double and int respectively, but you're passing string arguments. You need to convert those strings to double and int appropriately, e.g., with std::stod and std::stoi.

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Thank you. That was it, I had forgotten to convert to double and integers. That was something so simple that I've easily overlooked. You saved me hours of work. Now I was able to get my program to run, but I have another problem in the main function hopefully you can help. When you press 'A' to enter an employee , then press 'L' after that, it doesnt list anything. Have I gotten the pointers wrong or forgot to return something?


Attachment 15724

That's because you didn't actually add to the vector of pointers. And you really should be using unique_ptr, including for the vector.

Additionally, instead of a giant switch, separate the parts into functions, then call the functions from within the switch.

Another thing: declare variables near first use, i.e., stop declaring variables at one go near the top of functions, unless you can provide them with a sensible initial value at that point. Generally, your variables should exist in the smallest scope feasible, unless concerns such as efficiency dictate otherwise. This makes it easier to reason about your program as you only need to deal with the smallest amount of state at any point.

Oh, and header inclusion guards should go at the very top of headers, before the header includes other headers. Headers should not having using directives or using declarations at file scope; fully qualify names in headers as needed. Feel free to place using directives and using declarations in a local scope in headers though, or to use them in source files after the header inclusions. This helps to avoid namespace pollution and name collisions.

Yet another thing: you don't need the StaffMemberParser class as it is nothing more than a fancy namespace. I would get rid of it and rename parseStringToMember to parseStaffMember. That you're parsing from a string is obvious by the parameter type.

One other thing: sizeof(memberList) gives you the size of the vector object itself, which is a compile-time constant. It's never 0, even when the vector contains no elements. You need to use memberList.size() (which you do in the for loop a few lines down) to get the number of elements in the vector.

Quote:

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Originally Posted by christop

One other thing: sizeof(memberList) gives you the size of the vector object itself, which is a compile-time constant. It's never 0, even when the vector contains no elements. You need to use memberList.size() (which you do in the for loop a few lines down) to get the number of elements in the vector.

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Thank you. I figured out that problem well while i was doing debugging. I additionally forgot to add the Staff pointer to the vectorlist which is why the list function wouldn't work. So now it's working all great! Thanks for your help.