如果我有：
class Foo{
Bar** bars = new Bar*10;
};
class Bar{
string temp;
};
如果我有一系列 Foos：
Foo* foos = new Foo[5];
如果我想删除数组，应该像这样：
for(int i = 0; i < 5; i++)
{
for(int j = 0; j < 10; j++)
{
delete foos[i].bars[j];
}
delete[] foos[].bars;
}
delete[] foos;
？ 每次我尝试删除时都会抛出异常
还尝试只删除每个对象内的数组，而不删除数组的对象，但也失败了。 完整代码：
#include <iostream>
#include <string>
#include <cstdlib>
#include <ctime>
#include <random>
int MAX_BOOKS = 10;
using namespace std;
class Book {
private:
string title, author;
mutable bool canBook;
public:
Book(string x = "", string y = "", bool z = false) : title(x), author(y), canBook(z) {}
~Book() {}
Book(const Book& t)
{
this->title = t.title;
this->author = t.author;
this->canBook = t.canBook;
}
void print() {
string available;
cout << "title: " << this->title;
cout << " author: " << this->author;
if (this->canBook == true)
{
available = "yes";
}
else
{
available = "no";
}
cout << " canBook: " << available << endl;
}
string gettitle()
{
return title;
}
string getauthor() {
return author;
}
bool getcanBook() {
return canBook;
}
void settitle(string title)
{
this->title = title;
}
void setauthor(string author)
{
this->author = author;
}
void setcanBook(bool canBook) {
this->canBook = canBook;
}
};
class Reader {
private:
class Person {
private:
friend Reader;
string name, surname;
public:
Person(string x = "name", string y = "surname") {
name = x;
surname = y;
}
~Person() {}
string getname()
{
return name;
}
string getsurname() {
return surname;
}
void setname(string name)
{
this->name = name;
}
void setsurname(string surname)
{
this->surname = surname;
}
};
Person Person;
float penalty;
Book** booked = new Book*[MAX_BOOKS]; //books
int bookedNum; //currently booked
public:
//constructor
Reader(string a = "name", string b = "surname", float x = 0)
: Person(a, b), penalty(x), bookedNum(0) {
for (int i = 0; i < MAX_BOOKS; ++i)
{
booked[i] = new Book();
}
//booked = new Book * [MAX_BOOKS];
}
// copy-constructor
Reader(const Reader& t)
: Person(t.Person), penalty(t.penalty), bookedNum(t.bookedNum) {
booked = new Book * [bookedNum];
for (int i = 0; i < bookedNum; ++i) {
booked[i] = new Book(*t.booked[i]);
}
}
//destructor
~Reader() {
for (int i = 0; i < MAX_BOOKS; ++i) {
delete booked[i];
}
delete[] booked;
}
//copy-swap
Reader& operator=(const Reader& other){
Reader temp(other);
std::swap(temp.Person, Person);
std::swap(temp.penalty, penalty);
std::swap(temp.booked, booked);
std::swap(temp.bookedNum, bookedNum);
return *this;
}
Reader& operator=(Reader&& other) noexcept
{
if (this != &other)
{
this->Person = move(other.Person);
this->penalty = other.penalty;
this->bookedNum = other.bookedNum;
delete[] this->booked;
this->booked = other.booked;
other.booked = nullptr;
other.penalty = 0.0f;
other.bookedNum = 0;
}
return *this;
}
void setname(string name) {
this->Person.setname(name);
}
void setsurname(string surname) {
this->Person.setsurname(surname);
}
void setpenalty(float penalty) {
this->penalty = penalty;
}
void setliczbaKsiazek(int liczba) {
this->bookedNum = liczba;
}
string getname() {
return this->Person.getname();
}
string getsurname() {
return this->Person.getsurname();
}
float getpenalty() {
return penalty;
}
int getliczbaKsiazek() {
return bookedNum;
}
Book** getwypozyczona() {
return booked;
}
void print()
{
cout << "name: " << this->Person.getname() << " surname: " << this->Person.getsurname() << " penalty: " << this->penalty << " booked: ";
bool firstBook = true;
for (int i = 0; i < bookedNum; ++i)
{
if (!this->booked[i]->gettitle().empty())
{
if (!firstBook)
cout << ", ";
cout << this->booked[i]->gettitle() << ", " << this->booked[i]->getauthor();
firstBook = false;
}
}
cout << endl;
}
};
void stworz(Reader*& readers, int size)
{
readers = new Reader[size];
}
void stworz(Book*& books, int size)
{
books = new Book[size];
}
void zainicjuj(Book*& books, int size)
{
static random_device seed;
static default_random_engine dfe(seed());
uniform_int_distribution<int> distribution(0, 9);
string_view tytuly[10] = { "Diuna", "Wesele", "Obcy", "Gra", "Pomnik", "Tadeusz", "Zbrodnia", "Lalka", "Basnie", "Wiedzmin" };
string_view autorzy[10] = { "Mickiewicz", "Krasicki", "Slowacki", "Sienkiewicz", "Zajdel", "Dostojewski", "Prus", "Wyspianski", "Sapkowski", "Herbert" };
string tytulyv[10];
string autorzyv[10];
for (int i = 0; i < 10; i++)
{
tytulyv[i] = tytuly[i];
autorzyv[i] = autorzy[i];
}
for (int i = 0; i < size; i++)
{
int random = distribution(dfe);
int random2 = distribution(dfe);
books[i].settitle(tytulyv[random]);
books[i].setauthor(autorzyv[random2]);
books[i].setcanBook(true);
}
}
void pokaz(Reader*& readers, int size) {
for (int i = 0; i < size; i++)
{
readers[i].print();
}
}
void pokaz(Book*& books, int size) {
for (int i = 0; i < size; i++)
{
books[i].print();
}
}
void zwolnij(Reader*& readers, int& size)
{
string surname;
int id = -1;
cout << "Type in surname: " << endl;
cin >> surname;
for (int i = 0; i < size; i++)
{
if (readers[i].getsurname() == surname) {
id = i;
break;
}
}
if (id != -1)
{
Reader* temp = new Reader[size-1];
int j = 0;
for (int i = 0; i < size; i++)
{
if (i != id)
{
temp[j++] = readers[i];
}
}
for (int i = 0; i < size; i++)
{
delete[] readers[i].getwypozyczona();
}
delete[] readers;
readers = temp;
--size;
cout << "Usunieto czytelnika" << endl;
}
else {
cout << "Nie znaleziono czytelnika" << endl;
}
}
int main()
{
int ileCzytelnikow = 5;
Reader* readers = new Reader[ileCzytelnikow];
readers[0] = Reader("John", "Doe", 0); // Example data
readers[1] = Reader("Jane", "Smith", 0); // Example data
readers[2] = Reader("Alice", "Johnson", 0); // Example data
readers[3] = Reader("Bob", "Brown", 0); // Example data
readers[4] = Reader("Carol", "Davis", 0); // Example data
int ileKsiazek = 5;
Book* books = new Book[ileKsiazek];
int x = 0;
do {
cout << "Pick an action: \n";
cout << "1. Show readers \n";
cout << "2. Show books \n";
cout << "3. Delete a Reader \n";
//cout << "4. Check out a book \n";
cout << "5. End \n";
cin >> x;
switch (x) {
case 1:
pokaz(readers, ileCzytelnikow);
break;
case 2:
pokaz(books, ileKsiazek);
break;
case 3:
zwolnij(readers, ileCzytelnikow);
break;
case 4:
//borrow(readers, ile, books, ilosc);
break;
case 5:
return 0;
default:
cout << "Invalid prompt" << endl;
break;
}
} while (x != 5);
delete[] readers;
delete[] books;
return 0;
}
我相信这是我现在可以实现的最简单的版本，但我仍然无法识别导致异常的原因。
这就是你想要做的吗？您没有实例化二维数组的第二个维度。
class Foo{
public:
Bar ** bars;
Foo()
{
bars = new Bar*[10];
for(int i = 0; i < 10; ++i)
bars[i] = new Bar[10];
}
};
void DoDelete()
{
Foo* foos = new Foo[5];
for(int i = 0; i < 5; i++)
{
for(int j = 0; j < 10; j++)
{
delete [] foos[i].bars[j];
}
delete [] foos[i].bars;
}
delete[] foos;
}