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So I've been working on some code that focuses on Polymorphism and upon attempting to Link the files I get the following Linker errors:

main.cpp:(.text+0x1e7): undefined reference to `InstructionalAsst::InstructionalAsst(std::string, int, double)'

main.cpp:(.text+0x780): undefined reference to `Employee::getName()'

collect2: error: ld returned 1 exit status

I know this question has been asked a lot, and I did some research and I believe I understand what the issue is (That I haven't defined the constructor correctly) but when reviewing the code it looks like I have all the constructors I use properly defined. I'm at a loss at the moment so If someone could take a look and show me the error of my ways it would be greatly appreciated. Thanks in advance!

main.cpp

#include "std_lib_facilities.h"
#include "staff.h"
#include "employee.h"
#include "InstructionalAsst.h"
#include <sstream>
int main()
{

    //Create a Employee Vector
    vector<Employee*> employees; //Polymorphic Container
    string line;
    ifstream file("employee.txt");


    while(getline(file, line)) // Keeps going while lines are available.
    {

        istringstream iss(line);
        vector<string> info;
        string place;
        while(iss >> place)
        {
            info.push_back(place);
            cout << place << endl;
        }

        if(info.at(0) == "IA")
        {

            employees.push_back(new InstructionalAsst(info.at(1), stoi(info.at(2)), stod(info.at(3))));

        }
    }

    file.close();

    //Go through vector printing out name and total salary

    for(int i=0; i< employees.size(); ++i)
    {
        cout << "Name:" << employees.at(i)->getName() << "Salary:" << employees.at(i)->salary() << endl;
    }

    return 0;
}

employee.h

#ifndef EMPLOYEE_H_INCLUDED
#define EMPLOYEE_H_INCLUDED

#include "std_lib_facilities.h"

//Employee Header file

class Employee
{

public:
    Employee(string fullName, int years);
    string getName();
    int getYears();
    virtual double salary() = 0;
    virtual string info() = 0;

protected:
    string e_fullName;
    int e_years;
};

#endif //EMPLOYEE_H_INCLUDED

employee.cpp

#include "std_lib_facilities.h"
#include "employee.h"

//Employee source file

Employee::Employee(string fullName, int years)
{
    e_fullName = fullName;
    e_years = years;
}

string Employee::getName()
{
    return e_fullName;
}

int Employee::getYears()
{
    return e_years;
}

staff.h

#ifndef STAFF_H_INCLUDED
#define STAFF_H_INCLUDED

#include "std_lib_facilities.h"
#include "employee.h"

// Staff Header File

class Staff : public Employee
{
public:
    Staff(string fullName, int years, double sal);
    double salary();
    string info();
protected:
    double s_base_salary;

};

#endif //STAFF_H_INCLUDED

staff.cpp

#include "std_lib_facilities.h"
#include "staff.h"

// This is the Staff source file

Staff::Staff(string fullName, int years, double sal) : Employee(fullName, years)
{
    s_base_salary = sal;
}

double Staff::salary()
{
    return s_base_salary;
}

string Staff::info()
{
    return "Name: " +  getName() + "\nYears of service: " + to_string(getYears()) +  "\nSalary: " + to_string(salary());
}

InstructionalAsst.h

#ifndef INSTRUCTIONALASST_H_INCLUDED
#define INSTRUCTIONALASST_H_INCLUDED

#include "std_lib_facilities.h"
#include "staff.h"

//InstructionalAsst Header File

class InstructionalAsst : public Staff
{
public:
    InstructionalAsst(string fullName, int years, double sal);
    double salary();
    string info();
};

#endif //INSTRUCTIONALASST_H_INCLUDED

InstructionalAsst.cpp

#include "std_lib_facilities.h"
#include "InstructionalAsst.h"

// InsturctionalAsst Source File

InstructionalAsst::InstructionalAsst(string fullName, int years, double sal) : Staff(fullName, years, sal)
{
}

double InstructionalAsst::salary()
{
    return Staff::salary();
}


string InstructionalAsst::info()
{
    return "Name: " +  getName() + "\nYears of service: " + to_string(getYears()) + "\n Salary: " + to_string(salary());
}

std_lib_facilities.h

/*
 std_lib_facilities.h
 */

/*
 simple "Programming: Principles and Practice using C++ (second edition)" course header to
 be used for the first few weeks.
 It provides the most common standard headers (in the global namespace)
 and minimal exception/error support.

 Students: please don't try to understand the details of headers just yet.
 All will be explained. This header is primarily used so that you don't have
 to understand every concept all at once.

 By Chapter 10, you don't need this file and after Chapter 21, you'll understand it

 Revised April 25, 2010: simple_error() added

 Revised November 25 2013: remove support for pre-C++11 compilers, use C++11: <chrono>
 Revised November 28 2013: add a few container algorithms
 Revised June 8 2014: added #ifndef to workaround Microsoft C++11 weakness
 */

#ifndef H112
#define H112 251113L


#include <iostream>
#include <iomanip>
#include <fstream>
#include <sstream>
#include <cmath>
#include <cstdlib>
#include <string>
#include <list>
#include <forward_list>
#include <vector>
#include <unordered_map>
#include <algorithm>
#include <array>
#include <regex>
#include <random>
#include <stdexcept>

//------------------------------------------------------------------------------


//------------------------------------------------------------------------------

using Unicode = long;

//------------------------------------------------------------------------------

using namespace std;

template<class T> string to_string(const T& t)
{
    ostringstream os;
    os << t;
    return os.str();
}

struct Range_error : out_of_range { // enhanced vector range error reporting
    int index;
    Range_error(int i) :out_of_range("Range error: "+to_string(i)), index(i) { }
};


// trivially range-checked vector (no iterator checking):
template<class T> struct Vector : public std::vector<T> {
    using size_type = typename std::vector<T>::size_type;

#ifdef _MSC_VER
    // microsoft doesn't yet support C++11 inheriting constructors
    Vector() { }
    explicit Vector(size_type n) :std::vector<T>(n) { }
    Vector(size_type n, const T& v) :std::vector<T>(n,v) { }
    template <class I>
    Vector(I first, I last) : std::vector<T>(first, last) { }
    Vector(initializer_list<T> list) : std::vector<T>(list) { }
#else
    using std::vector<T>::vector; // inheriting constructor
#endif

    T& operator[](unsigned int i) // rather than return at(i);
    {
        if (i < 0 || this->size() <= i) throw Range_error(i);
        return std::vector<T>::operator[](i);
    }
    const T& operator[](unsigned int i) const
    {
        if (i < 0 || this->size() <= i) throw Range_error(i);
        return std::vector<T>::operator[](i);
    }
};

// disgusting macro hack to get a range checked vector:
#define vector Vector

// trivially range-checked string (no iterator checking):
struct String : std::string {
    using size_type = std::string::size_type;
    //  using string::string;

    char& operator[](unsigned int i) // rather than return at(i)
    {
        if (size() <= i) throw Range_error(i);
        return std::string::operator[](i);
    }

    const char& operator[](unsigned int i) const
    {
        if (size() <= i) throw Range_error(i);
        return std::string::operator[](i);
    }
};


namespace std {

    template<> struct hash<String>
    {
        size_t operator()(const String& s) const
        {
            return hash<std::string>()(s);
        }
    };

} // of namespace std


struct Exit : runtime_error {
    Exit(): runtime_error("Exit") {}
};

// error() simply disguises throws:
inline void error(const string& s)
{
    throw runtime_error(s);
}

inline void error(const string& s, const string& s2)
{
    error(s + s2);
}

inline void error(const string& s, int i)
{
    ostringstream os;
    os << s << ": " << i;
    error(os.str());
}


template<class T> char* as_bytes(T& i)  // needed for binary I/O
{
    void* addr = &i;  // get the address of the first byte
    // of memory used to store the object
    return static_cast<char*>(addr); // treat that memory as bytes
}


inline void keep_window_open()
{
    cin.clear();
    cout << "Please enter a character to exit\n";
    char ch;
    cin >> ch;
    return;
}

inline void keep_window_open(string s)
{
    if (s=="") return;
    cin.clear();
    cin.ignore(120,'\n');
    for (;;) {
        cout << "Please enter " << s << " to exit\n";
        string ss;
        while (cin >> ss && ss!=s)
            cout << "Please enter " << s << " to exit\n";
        return;
    }
}


// error function to be used (only) until error() is introduced in Chapter 5:
inline void simple_error(string s)  // write ``error: s and exit program
{
    cerr << "error: " << s << '\n';
    keep_window_open();   // for some Windows environments
    exit(1);
}

// make std::min() and std::max() accessible on systems with antisocial macros:
#undef min
#undef max


// run-time checked narrowing cast (type conversion). See ???.
template<class R, class A> R narrow_cast(const A& a)
{
    R r = R(a);
    if (A(r)!=a) error(string("info loss"));
    return r;
}

// random number generators. See 24.7.



inline int randint(int min, int max) { static default_random_engine ran; return uniform_int_distribution<>{min, max}(ran); }

inline int randint(int max) { return randint(0, max); }

//inline double sqrt(int x) { return sqrt(double(x)); } // to match C++0x

// container algorithms. See 21.9.

template<typename C>
using Value_type = typename C::value_type;

template<typename C>
using Iterator = typename C::iterator;

template<typename C>
// requires Container<C>()
void sort(C& c)
{
    std::sort(c.begin(), c.end());
}

template<typename C, typename Pred>
// requires Container<C>() && Binary_Predicate<Value_type<C>>()
void sort(C& c, Pred p)
{
    std::sort(c.begin(), c.end(), p);
}

template<typename C, typename Val>
// requires Container<C>() && Equality_comparable<C,Val>()
Iterator<C> find(C& c, Val v)
{
    return std::find(c.begin(), c.end(), v);
}

template<typename C, typename Pred>
// requires Container<C>() && Predicate<Pred,Value_type<C>>()
Iterator<C> find_if(C& c, Pred p)
{
    return std::find_if(c.begin(), c.end(), p);
}


// Initialize C++11 unique_ptr, at least until std::make_unique()
// becomes part of the standard (C++14)
template <typename Value, typename ... Arguments>
std::unique_ptr<Value> make_ptr(Arguments && ... arguments_for_constructor)
{
    return std::unique_ptr<Value>(
                                  new Value(std::forward<Arguments>(arguments_for_constructor)...)
                                  );
}

#endif //H112

employee.txt (Test Sample)

IA Joe_Blow 15 4000
LI Jane_Doe 25 6000 500
PF Henny_Penny 5 15 1025
IA Gnarly_Moe 15 5000
DH TaskMaster 5 10 1000 750
PF Holey_Moley 10 50 4025
IA John_Doe 10 4750
PF Jack_Black 2 5 500
Nate F.
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  • 2
  • Be sure to not forget to add ``std::`` or ``using namesapce std;`` where approvpriate! – BrainStone Mar 19 '16 at 16:23
  • it would also nice to have the compilation command you used – bibi Mar 19 '16 at 16:25
  • You are probably not compiling or at least not linking the other cpp files. – crashmstr Mar 19 '16 at 16:29
  • `main.cpp` includes `std_lib_facilities.h` which is not given in the sample, thus the compile fails. – karastojko Mar 19 '16 at 16:30
  • @BrainStone the using namespace std is called in the std_lib_facilities.h file, I forgot to include that code in the summary. – Nate F. Mar 19 '16 at 16:32
  • @bibi compilation command I used was g++ -std=c++11 main.cpp where the version of g++ is Apple LLVM version 7.0.2 (clang-700.1.81) Target: x86_64-apple-darwin15.2.0 Thread model: posix – Nate F. Mar 19 '16 at 16:36
  • Well as @crashmstr pointed out you need to compile all cpp files. Easiest way (assuming all cpp files are in the same directory and there are no files from other projects) ``g++ -std=c++11 *.cpp`` – BrainStone Mar 19 '16 at 16:39
  • @karastojko This isn't a compiler error though it is a linker error. However, I did forget to include the std_lib_facilities.h – Nate F. Mar 19 '16 at 16:40
  • @BrainStone How would I go about doing that? I thought all I had to do was compile the main.cpp and it would automatically pickup the other cpp files. – Nate F. Mar 19 '16 at 16:42
  • (I updated my previous comment already but here you go anyway) To compile all cpp files either list them all (separated by a space) or just use ``g++ -std=c++11 *.cpp``. If you want to give the the executable a specific name add the option ``-o name`` (With ``name`` being the name of the executable) – BrainStone Mar 19 '16 at 16:45
  • @BrianStone whoops missed the previous comment you added. My bad. – Nate F. Mar 19 '16 at 16:45
  • You might also want to look at makefiles when using servaral source files! – BrainStone Mar 19 '16 at 16:46
  • @BrainStone Yep, that did the trick. Thanks! and yeah I definitely need to look into those makefiles. – Nate F. Mar 19 '16 at 16:50

0 Answers0