I'm doing an assignment with virtual classes, I need to implement a pure virtual method which later will be implemented in an inherited class.
I solved a problem before with pure virtual methods which worked flawlessly, solving by myself the error i receive now ( error C2259: 'Playlist': cannot instantiate abstract class) - by implementing a method in an inherited class.
class Record
{
char* artist;
char* titlu;
int durata;
public:
Record()
{
artist = new char[50];
titlu = new char[50];
durata = 0;
}
void setArtist(char *s)
{
strcpy(artist, s);
}
char* getArtist()
{
return artist;
}
void setTitlu(char* s)
{
strcpy(titlu, s);
}
char* getTitlu()
{
return titlu;
}
void setDurata(int n)
{
int durata = n;
}
int getDurata()
{
return durata;
}
};
class Playlist
{
Record* p; /// "Record" is another class
public:
Playlist(int n)
{
p = new Record[n];
}
virtual void sortare(int n) = 0;
};
class PlaylistImplementation :public Playlist
{
public:
void sortare(int n)
{
if (n == 1)
{
cout << "1";
}
else if (n == 2)
{
cout << "2";
}
else
cout << "3";
}
};
Here is the main():
int main()
{
int n;
cout << "Number of tracks ?";
cin >> n;
Playlist x(n); /// I use VS 2019 and "x" has a red tilde underneath,
/// also error is at this line.
cin.ignore();
cin.get();
return 0;
}
I expect to instantiate an object from class Playlist.
You can't instantiate Playlist directly because it is abstract, so in main, instead of:
Playlist x(n);
you need
PlaylistImplementation x(n);
And you need a constructor in PlaylistImplementation like so:
PlaylistImplementation (int n) : PlayList (n) { }
Member 'p' of type Record in class Playlist is implicitly declared private. For access you need to add public member functions (e.g. to store data to a record).
Related
I am trying to implement a character selection method, for a text based game and i know that it will not work the way i did it, because i am returning a refernce to an object with a lifetime limited to the scope of the method call. I have also tried to implement the method without referencing the Fighter parent class and returning a child class (Samus and Ryu) based on the players character choice, but then i would get this error: invalid abstract return type 'Fighter'.
Fighter characterSelection(int player,bool checkForBot, Fighter &fig)
{
int input;
string newName;
if(checkForBot)
{
input = (rand()%2)+1;
}
else{
cout << "Please choose your Fighter player"<<player<<": \n1. Samus\n2. Ryu\n";
input = readInput<int>();
}
if(input == 1)
{
Samus sam;
if(checkForBot)
{
cout << "Bot selected Samus!";
}
else{
cout << "Player"<<player<<" selected Samus!\nDo you wish to change your fighters name?\n1.Yes\n2.No\n";
input = readInput<int>();
if(input == 1)
{
cout << "new Name: ";
newName = readInput<string>();
changeName(newName,sam);
}
}
return sam;
}
else if(input == 2)
{
Ryu ry;
if(checkForBot)
{
cout << "Bot selected Ryu!";
}
else {
cout << "Player"<<player<<" selected Ryu!\nDo you wish to change your fighters name?\n1.Yes\n2.No\n";
input = readInput<int>();
if(input == 1)
{
cout << "new Name: ";
newName = readInput<string>();
changeName(newName,ry);
}
}
return ry;
}
}
After having chosen one character and the end of the function call, the destructor of the object is called upon, thus making the reference linked to a non-existing object.
int main()
{
int input;
string newName;
bool checkForBot;
int player=1;
while(true)
{
cout << "1. PVP \n2. PVE\n";
input = readInput<int>();
if(input == 1)
{
checkForBot = false;
//Character Selection
Fighter &fig1 = characterSelection(player,checkForBot,fig1);
player++;
Fighter &fig2 = characterSelection(player,checkForBot,fig2);
//Battle
fightPVP(fig1, fig2);
}
else if(input ==2)
{
//Character Selection
Fighter &fig1 = characterSelection(player,checkForBot,fig1);
checkForBot = true;
Fighter &bot = characterSelection(player,checkForBot,bot);
//Battle
fightPVE(fig1, bot);
}
}
return 0;
}
Is there any other way i could solve this problem, instead of referencing the parent class and then creating the child in the function call?
In this:
Fighter &fig1 = characterSelection(player,checkForBot,fig1);
you are making a reference to a local object copy returned by the function.
Returning a parent object has also the issue of object slicing; you should have that in account.
If that's not a problem, however, you can add a copy constructor to the class and just remove the reference when declaring the receiving variable:
Fighter fig1 = characterSelection(player,checkForBot,fig1);
If your object is not suited to copy, other way is to new the object in characterSelection and return a pointer (or better, shared pointer) of the base class.
In the case of your code, the compiler is right. From the function 'characterSelection' you return an instance of the abstract class Fighter which is wrong as abstract classes cannot be instantiated. You can only return a pointer or a reference (Fighter* or Figther&) to an abstract class (the pointer is generally the preferred way). From my knowledge the single way to achieve what you want using inheritance form an abstract class and a choice of a kind of Fighter at runtime is that:
#include <iostream>
class Fighter
{
public:
virtual void f() = 0;
virtual ~Fighter() {};
};
class Samus : public Fighter
{
public:
void f() { std:: cout << "Samus\n"; }
};
class Ryu : public Fighter
{
public:
void f() { std:: cout << "Ryu\n"; }
};
Fighter* getFigther()
{
int fighterCode;
std::cin >> fighterCode;
switch (fighterCode)
{
case 0: return new Samus();
case 1: return new Ryu();
default: return nullptr;
}
}
int main()
{
Fighter* myF = getFigther();
// Do what you want with the fighter
myF->f();
// Release the resources
delete myF;
}
If you want to avoid heap allocation from whatever reason, you can do that by using placement new syntax:
#include <iostream>
class Fighter
{
public:
virtual void f() = 0;
virtual ~Fighter() {};
};
class Samus : public Fighter
{
public:
void f() { std:: cout << "Samus\n"; }
};
class Ryu : public Fighter
{
public:
void f() { std:: cout << "Ryu\n"; }
};
constexpr std::size_t size()
{
constexpr std::size_t samusS = sizeof(Samus);
constexpr std::size_t ryuS = sizeof(Ryu);
return samusS < ryuS ? ryuS : samusS;
}
void getFigther(Fighter*& f)
{
int fighterCode;
std::cin >> fighterCode;
// If figtherCode is invaild you can print a message or throw an exception
switch (fighterCode)
{
case 0: new (f) Samus(); break;
case 1: new (f) Ryu(); break;
}
}
int main()
{
char space[size()];
Fighter* myF = (Fighter*) (space);
getFigther(myF);
// Do what you want with the fighter
// No delete requied
myF->f();
}
However, if you have multiple fighter classes with different sizes you will need a compile-time function to give you the maximum size of any class (representing a fighter). I don't think that approach worth the effort in your case.
I have an abstract class "Mark" and it has a child class "Int_num". I also have a "Subject" class. I want a pointer to the address in the memory of the "Mark" class to be written to the "mark" parameter when calling its constructor. What should I do to make the mark pointer point to the "Mark" class?" occurred, after the compiler complaint about "expression must have class type" or something like that in mark.print_mark()?
class Mark {
private:
int mark;
public:
virtual void change_mark(int);
virtual void print_mark();
virtual int return_mark();
};
class Int_mark : public Mark {
private:
int mark;
public:
Int_mark();
Int_mark(int);
~Int_mark();
void change_mark(int = 0);
void print_mark() const;
int return_mark() const;
};
Int_mark::Int_mark() {
std::string str_mark;
std::cout << "New mark: ";
std::cin.ignore();
std::getline(std::cin, str_mark);
str_mark = ltrim(rtrim(str_mark));
int new_mark;
try {
new_mark = stoi(str_mark);
} catch(...) {
std::cout <<"wq";
mark = 1;
return ;
}
try {
if((new_mark < 1) || (new_mark > 5))
throw 1;
else
mark = new_mark;
} catch(int a) {
std::cout << "qw" << std::endl;
mark = 1;
}
}
void Int_mark::print_mark() const {
std::cout << "Mark: " << mark << std::endl;
}
Subject
#include "Mark.h"
#include <string>
#include <vector>
class Subject {
private:
std::string name_subject;
std::string type_subject;
unsigned hour_subject = 0;
void *mark = nullptr;
public:
Subject();
Subject(std::string, int);
Subject(std::string, bool);
~Subject();
void change_mark(unsigned);
void change_mark(bool);
void rename_subj(std::string);
void add_hour(unsigned);
};
Subject::Subject() {
std::string name_sub;
std::cout << "Введите название предмета: ";
getline(std::cin, name_sub);
name_sub = split_string(name_sub);
name_subject = name_sub;
int select = 2;
if(select == 1) {
type_subject = "Bool";
//mark = new Bool_mark();
} else {
type_subject = "Int";
mark = new Int_mark();
//What should I do to make the mark pointer point to the "Mark" class?
mark.print_mark();
}
}
main
#include "subject/Subject.h"
using namespace std;
int main() {
Subject q;
}
What am I doing wrong? How should I do this?
The pointer mark is of type void *. You could cast it with
static_cast<Int_mark*>(mark)
and call the function with
static_cast<Int_mark*>(mark)->print_mark();
But usually in OOP mark would be a pointer to the base class
Mark *mark = nullptr;
Now you can check for errors with
mark = new Int_mark();
auto *m = dynamic_cast<Int_mark*>(mark);
if (m)
m->print_mark();
Remember the virtual destructor in the base class
virtual ~Mark();
When to use virtual destructors?
Here is a fixed version of your code:
#include <iostream>
#include <string>
#include <vector>
class Mark {
public:
virtual ~Mark() = default;
//virtual void change_mark(int) = 0;
virtual void print_mark() const = 0;
//virtual int return_mark() const = 0;
};
class Int_mark : public Mark {
private:
int mark;
public:
Int_mark();
Int_mark(int);
~Int_mark() override = default;
//void change_mark(int = 0) override;
void print_mark() const override;
//int return_mark() const override;
};
Int_mark::Int_mark() {
std::string str_mark;
std::cout << "New mark: ";
std::cin.ignore();
std::getline(std::cin, str_mark);
//str_mark = ltrim(rtrim(str_mark));
int new_mark;
try {
new_mark = stoi(str_mark);
} catch(...) {
std::cout <<"wq";
mark = 1;
return ;
}
try {
if((new_mark < 1) || (new_mark > 5))
throw 1;
else
mark = new_mark;
} catch(int a) {
std::cout << "qw" << std::endl;
mark = 1;
}
}
void Int_mark::print_mark() const {
std::cout << "Mark: " << mark << std::endl;
}
class Subject {
private:
std::string name_subject;
std::string type_subject;
unsigned hour_subject = 0;
Mark *mark = nullptr;
public:
Subject();
Subject(std::string, int);
Subject(std::string, bool);
~Subject();
void change_mark(unsigned);
void change_mark(bool);
void rename_subj(std::string);
void add_hour(unsigned);
};
Subject::Subject() {
std::string name_sub;
std::cout << "Введите название предмета: ";
getline(std::cin, name_sub);
//name_sub = split_string(name_sub);
name_subject = name_sub;
int select = 2;
if(select == 1) {
type_subject = "Bool";
//mark = new Bool_mark();
} else {
type_subject = "Int";
mark = new Int_mark();
auto *m = dynamic_cast<Int_mark*>(mark);
if (m)
m->print_mark();
}
}
Subject::~Subject() {
delete mark;
}
int main() {
Subject q;
}
Since I did not correctly understand the question in the first place, here a way how you can call the member function of base class Mark by object of derived class Int_Mark:
Int_mark *mark = new Int_mark();
mark->print_mark(); // calls member of the class Int_mark
mark->Mark::print_mark(); // calls member of the class Mark
Make sure that Mark::print_mark() is also defined and not just Int_mark::print_mark()
This code isn't compiled. All problems in virtual function attack() in basic class.
It hasn't got acces to massive in class Team. I was trying do theese classes friend.But it do not work whatever. Also I've done function ptr but it don't work.
Virtual function don't work in inherited classes too. Visual studio 2015 shows errors:
C2228, C2227, C2027.
Please help.
class Team;
class Unit
{
protected:
int hp;
int dmg;
int doodge;
public:
Unit(int hp, int dmg, int doodge): hp(hp), dmg(dmg), doodge(doodge){}
int GetHP()
{
return hp;
}
void SetHP(int hp)
{
this->hp = hp;
}
virtual void attack(Team &T)
{
int id = rand() % 3;
for (int i = 0; i < 3; i++)
if (typeid(*this) == typeid(T.arr[i]))
{
id = i;
break;
}
if (T.arr[id] <= 0)
return;
else
T.arr[id]->SetHP(T.arr[id]->GetHP() - this->dmg);
}
};
class Swordsman:public Unit
{
public:
Swordsman():Unit(15,5,60){}
//virtual void attack(Team & T)override
//{
// int id = rand() % 3;
// for (int i = 0; i < 3; i++)
// if (typeid(Swordsman) == typeid())
// {
// id = i;
// break;
// }
// if (*T.arr[id]->GetHP <= 0)
// return;
// else
// *T.arr[id]->SetHP(T.arr[id]->GetHP() - dmg);
//}
};
class Archer :public Unit
{
public:
Archer() :Unit(12, 4, 40) {}
//virtual void attack(Team & T)override
//{
// int id = rand() % 3;
// for (int i = 0; i < 3; i++)
// if (typeid(Archer) == typeid())
// {
// id = i;
// break;
// }
// if (*T.arr[id]->GetHP <= 0)
// return;
// else
// *T.arr[id]->SetHP(T.arr[id]->GetHP() - dmg);
//}
};
class Mage :public Unit
{
public:
Mage() :Unit(8, 10, 30) {}
/*virtual void attack(Team & T)override
{
int id = rand() % 3;
for (int i = 0; i < 3; i++)
if (typeid(*this) == typeid())
{
id = i;
break;
}*/
};
class Team
{
static short counter;
string name;
Unit* arr[3];
public:
Team()
{
name = "Team " + counter++;
for (int i = 0; i < 3; i++)
{
int selecter = rand() % 3;
switch (selecter)
{
case 0:
arr[i] = new Swordsman();
break;
case 1:
arr[i] = new Archer();
break;
case 2:
arr[i] = new Mage();
break;
}
}
}
~Team()
{
delete[]arr;
}
Unit * ptr(int id)
{
return arr[id];
}
bool check()
{
bool res = false;
for (int i = 0; i < 3; i++)
if (arr[i]->GetHP() > 0)
res = true;
return res;
}
void print()
{
cout << endl << "\t\t" << name << endl << endl;
cout << "\t" << typeid(*arr[0]).name() << endl;
cout << "\t" << typeid(*arr[1]).name() << endl;
cout << "\t" << typeid(*arr[2]).name() << endl;
}
friend class Unit;
};
short Team::counter = 0;
class Game
{
Team A, B;
public:
int Play()
{
while (true)
{
A.ptr(1)->attack(B);
if (A.check())
return 1;
else if (B.check())
return 2;
}
}
};
int main()
{
return 0;
}
Omitting anything irrelevant:
class Team;
class Unit
{
public:
virtual void attack(Team &T)
{
if(typeid(*this) == typeid(T.arr[i]))
// ^^^
{ }
}
};
You are accessing a member of class Team, but at the time given, you only have provided the declaration of Team... Side note: this is not specific to virtual functions, but would occur with any code you write.
Your problem now is that function implementations of both classes Team as well as Unit rely on the complete definition of the other class. So only solution to the problem is to implement one of the functions outside the class, e. g.:
class Team;
class Unit
{
public:
// requires Team, so only declared, not implemented!
virtual void attack(Team &T);
// ^
};
class Team
{
// complete definition!
};
void Unit::attack(Team& t)
{
// now implementation of...
}
Another minor problem is that arr member is private. Well, you provided a getter already (ptr), so use it (and give it a better name...).
If you want to go further towards a clean design, split your units and the team into different compilation units, each coming with a header and a source file:
unit.h:
class Team;
class Unit
{
// private members
public:
// only declarations as above, including constructor/destructor
// by the way: you are lacking a virtual destructor!!!
virtual ~Unit();
};
unit.cpp:
#include "unit.h"
#include "team.h" // fetch the definition of Team!
Unit(/*...*/) { }
Unit::~Unit() { }
// function definitions as shown above...
You would do the same for Team and even your Unit derived classes as well as the Game class. Be aware, though, that you need the complete class definition available if you want to inherit, so you need to include unit.h already int the headers:
archer.h:
#include "unit.h"
class Archer : public Unit
{
// again, only function declarations...
// as base class has already a virtual destructor, own destructor
// gets virtual implicitly (even the default one), so if you do
// not need it, you do not have to define it...
};
archer.cpp:
#include "archer.h"
// and whatever else needed, solely, unit.h already comes with archer.h
// implementations...
A program that stores a phone company's consumers data in a linked list. At the end it displays the bill for each human. I have the following codes:
class BaseTypeOfContract
{
private:
int minutePrice;
int SMSPrice;
public:
void setminutePrice(int x) { minutePrice = x; }
void setSMSPrice(int x) { SMSPrice = x; }
virtual int calculateBill(int talkedMinutes, int sentSMS) = 0;
int getminutePrice() const { return minutePrice; }
int getSMSPrice() const { return SMSPrice; }
};
class SMSBaseType : public BaseTypeOfContract
{
private:
int freeSMS;
public:
SMSBaseType(int minutePrice, int SMSPrice, int freeSMS)
{
setminutePrice(minutePrice);
setSMSPrice(SMSPrice);
setfreeSMS(freeSMS);
}
public:
void setfreeSMS(int free) { this->freeSMS = free; }
virtual int calculateBill(int talkedMinutes, int sentSMS)
{
int billedSMS = (freeSMS > sentSMS) ? 0 : sentSMS - freeSMS;
return talkedMinutes * getminutePrice() + billedSMS * getSMSPrice();
}
};
class Base : public BaseTypeOfContract
{
public:
Base()
{
setminutePrice(30);
setSMSPrice(10);
}
virtual int calculateBill(int talkedMinutes, int sentSMS) { return talkedMinutes * getminutePrice() + sentSMS * getSMSPrice();}
};
class SMSMax : public SMSBaseType
{
public:
SMSMax() : SMSBaseType(20, 5, 150) {}
};
class MobiNET: public SMSBaseType
{
public:
MobiNET() : SMSBaseType(10, 15, 25) {}
};
Client's class:
class Client
{
public:
std::string name;
std::string phoneNumber;
BaseTypeOfContract* typeOfContract;
int talkedMinutes;
int sentSMS;
Client *next;
public:
Client(){}
Client(std::string n, std::string p, int bp, int ks) : name(n), phoneNumber(p), talkedMinutes(bp), sentSMS(ks) {}
void preSetPlan(std::string s)
{
if (s == "MobiNET")
this->typeOfContract = new MobiNET();
else if (s == "SMSMax")
this->typeOfContract = new SMSMax();
else this->typeOfContract = new Base();
}
std::string getname() const { return name; }
std::string getphoneNumber() const { return phoneNumber; }
void setname(std::string n) { name = n; }
void setphoneNumber(std::string pn) { phoneNumber = pn; }
void settalkedMinutes(int bp) { talkedMinutes = bp; }
void setsentSMS(int SSMS) { sentSMS = SSMS; }
int getBill() const { return this->typeOfContract->calculateBill(talkedMinutes, sentSMS); }
};
I read the data from 2 files. First file contains the name, phone number, type of contract. Second file contains the phone number, talked minutes and sent SMS.
Client* file_read_in()
{
std::ifstream ClientData;
ClientData.open("clients.txt");
Client *first = new Client;
first = NULL;
while (!ClientData.eof())
{
std::string name, phoneNumber, typeOfContract;
ClientData >> name;
ClientData >> phoneNumber;
ClientData >> typeOfContract;
std::ifstream ClientTalkedSent;
ClientTalkedSent.open("used.txt");
while(!ClientTalkedSent.eof())
{
std::string phoneNumber2;
ClientTalkedSent >> phoneNumber2;
if (phoneNumber2 == phoneNumber)
{
int talkedMinutes, sentSMS;
ClientTalkedSent >> talkedMinutes;
ClientTalkedSent >> sentSMS;
Client* tmp = new Client(name, phoneNumber, talkedMinutes, sentSMS);
tmp->preSetPlan(typeOfContract);
tmp->next = NULL;
if (first == NULL)
{
first = tmp;
}
else
{
Client *cond = first;
while (cond->next != NULL) cond = cond->next;
cond->next = tmp;
}
}
}
ClientTalkedSent.close();
}
ClientData.close();
return first;
}
And the main:
int main()
{
Client* first = file_read_in();
while(first != NULL)
{
std::cout << first->getname() << " " << first->getphoneNumber() << " " << first->getBill() << std::endl;
first = first->next;
}
return 0;
}
My problem that I should free the allocated memory but I got on idea how. Which class' destructor should do the dirty job. I would appreciate if someone could use my code, to show how the "destructor inheritance" works.
Sorry for my bad english and thanks for the help. This site helped me alot of times, but for this problem I did not find a solution.
If you have a pointer BaseTypeOfContract* typeOfContract; that is used to point to different derived classes, then BaseTypeOfContract needs to have a virtual destructor for delete typeOfContract to work.
And as Client seems to create the objects pointed to, it also ought to be responsible for cleaning them up. Either by using delete typeOfContract; in its destructor, or by storing a smart pointer to get the work done automatically.
The other part is that each Client stores a pointer to the next Client. That seems like not the best design. In real life it is not at all like each person knowing who is the next person that buys a cell phone in the same store. :-)
You would be much better of with a container, like std::vector<Client>, that would also handle the lifetime of the Client objects.
I'm trying to inherit the name,skeletonType, and numLegs from my base class to my derived class.
I have a base class named Invertebrates and derived class named Spider. I want to be able to use the private variables with the derived class from my base class. I keep getting a compiling error on line 47 and it says expected primary-expression before ','.
I'm trying to get my output to look like this:
Spider:Brown Recluse, number of legs = 8, skeleton type = EXOSKELETON
Could someone help me out and point me in the right direction please. Here is what I put together so far.
// invertebrates.h
// invertebrate specifications
#ifndef _INVERTEBRATE_H_
#define _INVERTEBRATE_H_
#include <iostream>
using namespace std;
enum Skeleton_Type { NONE, HYDROSTATIC, EXOSKELETON };
class Invertebrate {
private:
string name;
Skeleton_Type skeletonType;
int numLegs;
protected:
void setSkeletonType(Skeleton_Type skeletonType);
void setNumLegs(int numLegs);
public:
Invertebrate();
Invertebrate(string name, Skeleton_Type skeletonType, int numLegs);
string getName();
Skeleton_Type getSkeletonType();
int getNumLegs();
virtual void print() = 0;
};
class Spider : public Invertebrate {
private:
const string NAME_PREFIX = "Spider: ";
public:
Spider();
Spider(string name);
virtual void print();
};
#endif // _INVERTEBRATE_H_
**********************************************************************
//invertebrates.cpp
#include "invertebrate.h"
void Invertebrate::setSkeletonType(Skeleton_Type skeletonType)
{
this->skeletonType = skeletonType;
}
void Invertebrate::setNumLegs(int numLegs)
{
this->numLegs = numLegs;
}
Invertebrate::Invertebrate()
{
name = "noName";
skeletonType = NONE;
numLegs = 0;
}
Invertebrate::Invertebrate(string name, Skeleton_Type skeletonType, int numLegs)
{
this->name = name;
this->skeletonType = skeletonType;
this->numLegs = numLegs;
}
string Invertebrate::getName()
{
return this->name;
}
Skeleton_Type Invertebrate::getSkeletonType()
{
return this->skeletonType;
}
int Invertebrate::getNumLegs()
{
return this->numLegs;
}
Spider::Spider(string name):Invertebrate(name,EXOSKELETON,8)
{
name = Invertebrate::getName();
}
void Spider::print()
{
string strSkType = "";
if(this->getSkeletonType() == 0)
strSkType= "none";
else if(this->getSkeletonType() == 1)
strSkType= "Hydrostatic";
else if(this->getSkeletonType() == 2)
strSkType= "exoskeleton";
cout << this->NAME_PREFIX + getName();
cout << ", number of legs = " << this->getNumLegs() << ", skeleton type = " << strSkType << endl;
}
int main()
{
Spider *sp = new Spider("Brown Recluse");
sp->print();
return 0;
}
OUTPUT:
Here are the issues in your code :-
In .h file -
const string NAME_PREFIX = "Spider: ";
is not a valid way to initialize cont members - const should be initialized through constructor initializer list (till C++11).
Correct way in .cpp
Spider::Spider(string name):NAME_PREFIX(name),Invertebrate(name,EXOSKELETON,8)
{
name = NAME_PREFIX + Invertebrate::getName();
}
In the same constructor you have written name&, which is wrong, just pass name.
Spider::Spider(string
name):NAME_PREFIX(name),Invertebrate(name,EXOSKELETON,8)
I think I finally discovered what your line 47 is:
Spider::Spider(string name):Invertebrate(name&,EXOSKELETON,8)
{
name = NAME_PREFIX + Invertebrate::getName();
}
This function has two problems:
What is that & in name&? That is not valid syntax!
You cannot access this->name directly, because it is private in the base class. Instead here you are modifying the local name argument, and that does nothing useful.
You could make the base name public or protected. Or you could add a setName() protected function.
But in my opinion this member is ok being private and read-only. The solution would be to specify the proper name at construction time:
Spider::Spider(string name)
:Invertebrate(NAME_PREFIX + name, EXOSKELETON, 8)
{
}