exception unhandled violation access - c++

Question

I was using a dynamic array to expand it in the function assignbook and I have no idea why when I delete[] the array it gives me unhandled access violation.
this is the main
int main() {
Translator t;
Book b;
t.AssignBook(b);
t.AssignBook(b);
t.AssignBook(b);
t.AssignBook(b);
t.AssignBook(b);
t.AssignBook(b);
t.AssignBook(b);
t.AssignBook(b);
t.AssignBook(b);
t.AssignBook(b);
t.AssignBook(b);
t.AssignBook(b);
cout << t.getNumBooks();
}
and this is the implementation of translator class :
void Translator::AssignBook(Book& x) {
if (numBooks < size) {
translatebooks[numBooks] = x;
numBooks++;
}
else {
size += 10;
Book* t = new Book[size];
for (int i = 0; i < numBooks; i++) {
t[i] = translatebooks[i];
}
delete[] translatebooks;
translatebooks = t;
translatebooks[numBooks] = x;
cout << "The array is too small so it expanded from size " << numBooks << " to " << size << endl;
numBooks++;
}
}
and this is the error:
I'm so done with this error, please help. I do delete the array again in the destructor, though.
When I remove the delete[] statement it works, but still it gives me the weird accesss thing. :/
there's the whole code :
#include<iostream>
#include<string>
#define size1 2
using namespace std;
class Date {
private:
int Day;
int Month;
int Year;
public:
Date();
Date(int, int, int);
int getDay() const;
int getMonth() const;
int getYear() const;
void setDate(int, int, int);
void setMonth(int);
void setYear(int);
void setDay(int);
void print() const;
};
class Person {
private :
int PID;
string Pname;
public :
Person();
Person(int, string);
int getPID() const;
string getPname() const;
void setPID(int);
void setPerson(int, string);
void setPname(string);
void print() const;
};
class Book {
private:
int ISBN;
string BookTitle;
int NumPages;
string Language;
Date PublishingDate;
int NumAuthors;
Person* Authors;
public:
Book();
Book(int, string, int, string, Date&, int);
~Book();
void setISBN(int);
void setBookTitle(string);
void setLanguage(string);
void setNumPages(int);
void setPublishDate(Date&);
void setNumberAuthors(int);
void setAuthor(Person&);
int getISBN() const;
string getBookTitle() const;
string getLanguage() const;
int getNumPages() const;
Date getPublishDate() const;
int getNumberAuthors() const;
void print() const;
};
class Employee {
private:
Person Ename;
double salary;
protected:
int Rank;
public:
Employee();
Employee(Person&, double ,int);
void setEname(Person&);
void setSalary(double);
void setRank(int);
Person getEname() const;
int getRank() const;
virtual bool isManager() ;
virtual double getNetSalary();
double getSalary() const;
void print() const;
virtual void AssignBook(Book&);
};
class Translator:public Employee{
private:
int Experience;
int numBooks;
Book *translatebooks;
int size;
public :
void setExperience(int);
void AssignBook(Book&);
void unAssignBook(int ISBN);
double getNetSalary() const;
int getExperience() const;
int getNumBooks() const;
Translator();
Translator(Person&, double, int,int);
~Translator();
bool isManager();
void print() const;
};
class Manager : public Employee {
private:
bool certified;
public :
void setCertified(bool x);
bool getCertified();
Manager();
Manager(Person&, double, int,bool);
~Manager();
bool isManager();
};
Employee* ReadOneEmployee() {
int x;
cout << "Please Enter 1 for Translator \n 2 for Manager\n";
cin >> x;
if (x == 1) {
cout << "Name :" << endl;
string name;
cin >> name;
cout << "Rank: \n";
int Rank;
cin >> Rank;
cout << "Experience\n";
int Experience;
cin >> Experience;
cout << "Salary \n";
double salary;
cin >> salary;
cout << "ID =\n";
int ID;
cin >> ID;
Person P(ID, name);
return new Translator(P, salary, Rank, Experience);
}
else if (x == 2) {
cout << "Name :" << endl;
string name;
cin >> name;
cout << "Rank: \n";
int Rank;
cin >> Rank;
cout << "Certified:\n";
bool Experience;
cin >> Experience;
cout << "Salary \n";
double salary;
cin >> salary;
cout << "ID =\n";
int ID;
cin >> ID;
Person P(ID, name);
return new Manager(P, salary, Rank, Experience);
}
}
double Tax = 0.2;
int main() {
Book books[200];
Person z(2,"Meh");
Person x(2, "xd");
books[0].setAuthor(z);
books[0].setAuthor(x);
books[0].setNumPages(5);
Employee *list[size1];
for (int i = 0; i < size1; i++) {
list[i] = ReadOneEmployee();
}
int booksnum = 123;
int i = 0;
while (booksnum >= 0) {
if (!list[i]->isManager() && i<size1) {
list[i]->AssignBook(books[booksnum]);
i++;
}
else if (i >= size1) {
i = 0;
}
booksnum--;
}
for (int i = 0; i < size1; i++) {
cout << "Name :" << list[i]->getEname().getPname() << endl;
cout << "Salary =" << list[i]->getSalary() << endl;
cout << "Net Salary =" << list[i]->getNetSalary() << endl;
}
double totalN = 0,totalS=0;
for (int i = 0; i < size1; i++) {
totalN += list[i]->getNetSalary();
totalS += list[i]->getSalary();
}
cout << "Total Salary is :" << totalS << endl;
cout << "Total Net Salary is :" << totalN << endl;
int totalP = 0;
for (int i = 0; i < 200; i++) {
totalP += books[i].getNumPages();
}
cout << "Total Pages is :" << totalP << endl;
int max = 0;
for (int i = 0; i < 200; i++) {
if (books[i].getNumberAuthors() > max) {
max = books[i].getNumberAuthors();
}
}
for (int i = 0; i < 200; i++) {
if (books[i].getNumberAuthors() == max) {
books[i].print();
}
}
}
//i used regions to make it easier to read!
#pragma region Date_Implementation
Date::Date() {
Day = Month = 1;
Year = 1900;
}
Date::Date(int x,int y,int z) {
setDate(x, y, z);
}
int Date::getDay() const {
return Day;
}
int Date::getMonth() const {
return Month;
}
int Date::getYear() const {
return Year;
}
void Date::setDate(int x, int y, int z) {
setDay(x);
setMonth(y);
setYear(z);
}
void Date::setMonth(int x) {
if (x > 0 && x <= 12) {
Month = x;
}
else {
cout << "Invalid Value for the Months and it's been set to 1\n";
Month = 1;
}
}
void Date::setYear(int x){
if (x >= 1900) {
Year = x;
}
else {
cout << "Invalid Value for the Years and it's been set to 1900\n";
Year = 1900;
}
}
void Date::setDay(int x) {
if (x > 0 && x <= 31) {
Day = x;
}
else {
cout << "Invalid Value for the Days and it's been set to 1\n";
Day = 1;
}
}
void Date::print() const {
cout << "The Date is: " << Day << "/" << Month << "/" << Year << endl;
}
#pragma endregion
#pragma region Person_Implemntation
Person::Person() {
Pname = "";
PID = 1;
}
Person::Person(int x, string y) {
setPerson(x, y);
}
void Person ::setPerson(int x, string y) {
setPname(y);
setPID(x);
}
int Person::getPID() const {
return PID;
}
string Person::getPname() const {
return Pname;
}
void Person::setPID(int x) {
if (x > 0) {
PID = x;
}
else {
cout << "Invalid Value for PID it's been set to 1\n";
PID = 1;
}
}
void Person::setPname(string x) {
if (x != "") {
Pname = x;
}
else {
cout << "Invalid Value for Pname it's been set to \"\"\n";
Pname="";
}
}
void Person::print() const {
cout << "Person's name = " << Pname << endl;
cout << "Person's ID = " << PID << endl;
}
#pragma endregion
#pragma region Book_Implementation
Book::Book() {
ISBN = NumPages = 1;
Authors = new Person[3];
BookTitle = "";
Language = "English";
NumAuthors = 0;
PublishingDate.setDate(1, 1, 1900);
}
Book::Book(int x, string y, int z, string c, Date& v, int b) {
setISBN(x);
setBookTitle(y);
setNumPages(z);
setLanguage(c);
setPublishDate(v);
NumAuthors = 0;
}
Book::~Book() {
// cout << "Book " << BookTitle << " Destructed\n";
delete[] Authors;
}
void Book::setISBN(int x) {
if (x > 0) {
ISBN = x;
}
else {
cout << "Invalid Value for ISBN it's been set to 1\n";
ISBN = 1;
}
}
void Book::setBookTitle(string x) {
if (x != "") {
BookTitle = x;
}
else {
cout << "Invalid value for Book title it's been set to \"\"\n";
BookTitle = "";
}
}
void Book::setLanguage(string x) {
if (x == "English" ||x=="Arabic") {
BookTitle = x;
}
else {
cout << "Invalid value for Book's Language it's been set to English\n";
BookTitle = "English";
}
}
void Book::setNumPages(int x) {
if (x > 0) {
NumPages = x;
}
else {
cout << "Invalid Value for Number of Pages it's been set to 1\n";
NumPages = 1;
}
}
void Book::setPublishDate(Date& x) {
PublishingDate.setDate(x.getDay(), x.getMonth(), x.getYear());
}
void Book::setNumberAuthors(int x) {
if (x > 0 && x<=3) {
NumAuthors = x;
}
else {
cout << "Invalid Value for Number of authors it's been set to 1\n";
NumAuthors = 1;
}
}
void Book::setAuthor(Person& x) {
if (NumAuthors < 3) {
Authors[NumAuthors].setPerson(x.getPID(), x.getPname());
NumAuthors++;
}
else cout << "Can't set an author cause the array is full!!\n";
}
int Book::getISBN() const {
return ISBN;
}
string Book::getBookTitle() const {
return BookTitle;
}
int Book::getNumPages() const {
return NumPages;
}
Date Book::getPublishDate() const {
return PublishingDate;
}
int Book::getNumberAuthors() const {
return NumAuthors;
}
string Book::getLanguage() const {
return Language;
}
void Book::print() const {
cout << "ISBN = " << ISBN << endl;
cout << "BookTitle = " << BookTitle << endl;
cout << "Number of Pages = " << NumPages << endl;
cout << "Language = " << Language << endl;
cout << "The Authors that were set :\n";
for (int i = 0; i < NumAuthors; i++) {
Authors[i].print();
}
}
#pragma endregion
#pragma region Employee_Implementation
Employee::Employee() {
Rank = salary = 0;
Ename.setPerson(1, "Default");
}
Employee::Employee(Person& x, double y, int z) {
setEname(x);
setRank(z);
setSalary(y);
}
void Employee::setEname(Person& x) {
Ename.setPerson(x.getPID(), x.getPname());
}
void Employee::setSalary(double x) {
if (x > 0) {
salary = x;
}
else {
cout << "Invalid Value for Salary it's been set to 0\n";
salary = 0;
}
}
void Employee::setRank(int x) {
if (x >= 0) {
Rank = x;
}
else {
cout << "Invalid Value for Rank it's been set to 0\n";
Rank = 0;
}
}
Person Employee::getEname() const {
return Ename;
}
int Employee::getRank() const {
return Rank;
}
double Employee::getSalary() const {
return salary;
}
double Employee::getNetSalary() {
double totalS = salary + (Rank * 320);
double Net_Salary = totalS - totalS * Tax;
return Net_Salary;
}
void Employee::print() const {
Ename.print();
cout << "Rank = " << Rank<<endl;
cout << "salary = " << salary << endl;
}
bool Employee :: isManager() {
return false;
}
void Employee::AssignBook(Book& x) {
cout << "Can't cause it's just an Employee!";
}
#pragma endregion
#pragma region Translator_Implementation
void Translator::setExperience(int x) {
if (x >= 0) {
Experience = x;
}
else
{
cout << "Invalid Value for The Experience it's been set to 0\n";
Experience = 0;
}
}
void Translator::AssignBook(Book& x) {
if (numBooks < size) {
translatebooks[numBooks] = x;
numBooks++;
}
else {
size += 10;
Book* t = new Book[size];
for (int i = 0; i < numBooks; i++) {
t[i] = translatebooks[i];
}
delete[] translatebooks;
translatebooks = t;
translatebooks[numBooks] = x;
cout << "The array is too small so it expanded from size " << numBooks << " to " << size << endl;
numBooks++;
}
}
void Translator::unAssignBook(int ISBN) {
for (int i = 0; i < numBooks; i++) {
if (translatebooks[i].getISBN() == ISBN) {
for (int j = i; j < numBooks-1; j++) {
translatebooks[j] = translatebooks[j + 1];
}
numBooks--;
break;
}
}
}
double Translator::getNetSalary() const {
int total = 1;
for (int i = 0; i < numBooks; i++) {
total += translatebooks[i].getNumPages();
}
return getNetSalary() + 5 * total;
}
int Translator::getExperience() const {
return Experience;
}
int Translator::getNumBooks() const {
return numBooks;
}
Translator::Translator():Employee() {
Experience = 0;
numBooks = 0;
size = 10;
translatebooks = new Book[size];
}
Translator::Translator(Person& x, double y, int z, int c) :Employee(x, y, z) {
setExperience(c);
numBooks = 0;
size = 10;
translatebooks = new Book[size];
}
Translator::~Translator() {
delete[] translatebooks;
translatebooks = NULL;
}
bool Translator:: isManager() {
return false;
}
void Translator::print() const{
Employee::print();
cout << "Experience = " << Experience << endl;
cout << "Number of books = " << numBooks << endl;
cout << "And they are :\n";
if (numBooks == 0) cout << "None\n";
else
for (int i = 0; i < numBooks; i++) {
translatebooks[i].print();
}
}
#pragma endregion
#pragma region Manger_Implementation
void Manager::setCertified(bool x) {
certified = x;
}
bool Manager::getCertified() {
return certified;
}
Manager::Manager():Employee() {
certified = false;
}
Manager::Manager(Person& x, double y , int z, bool c):Employee(x,y,z) {
certified = c;
}
Manager::~Manager() {
cout << "Manager Destructed\n";
}
bool Manager::isManager() {
return true;
}
#pragma endregion

Answer 1

You have a rule of 0/3/5 violation. You have no copy constructor for Book. So when your code does:
for (int i = 0; i < numBooks; i++) {
t[i] = translatebooks[i];
}
This invokes the default copy constructor for Book. This is a disaster because the destructor looks like this:
Book::~Book() {
// cout << "Book " << BookTitle << " Destructed\n";
delete[] Authors;
}
So the default copy constructor gives both Book objects the same value for Authors. Whichever one is destroyed first deletes it. That leaves the other one with a pointer to nowhere.
Then this code runs when you expand the array:
delete[] translatebooks;
This destroys the books you copied, destroying the Authors arrays in the copies.
Moral: Don't use raw pointers. Don't use raw arrays. We have lots of classes that make all this stuff easy, why make it hard?