用于数组的delete p324

delete 对象地址;

delete 首先调用待清除对象的析构函数，然后释放内存

如果delete一个void指针，唯一发生的事情就是释放了内存。因为通过void指针，无法知道对象的类型，就无法调用其析构函数。

delete []books;

[]告诉编译器，books实际上是一个对象数组的起始地址。该代码的任务是，把数组创建时存放在某处的数组元素个数取回，并为数组的所有对象调用析构函数。

 1 #include <iostream>
 2 #include <string>
 3
 4 using namespace std;
 5
 6 class Book
 7 {
 8     string name;
 9     string author;
10     double price;
11
12 public:
13     Book() : name("null"), author("null"), price(0) {}
14     Book(string name, string author, double price) : name(name), author(author), price(price) {}
15
16     //复制构造函数
17     Book(const Book& b) : name(b.name), author(b.author), price(b.price)
18     {
19         cout << "Book::Book(const Book& b)" << endl;
20     }
21
22     ~Book()
23     {
24         cout << "~Book()" << endl;
25         cout << "释放书名为：‘" << name << "‘占用的内存" << endl;
26     }
27
28     friend ostream& operator<<(ostream& os, const Book& b)
29     {
30         return os << "BookName: " << b.name << ", BookAuthor: " << b.author
31             << ", BookPrice: " << b.price;
32     }
33
34     //重载赋值运算符
35     Book& operator=(const Book& b)
36     {
37         cout << "Book::operator=(const Book&)" << endl;
38         name = b.name;
39         author = b.author;
40         price = b.price;
41
42         return *this;
43     }
44 };
45
46
47 int main()
48 {
49     //数组book里放的是Book类型的指针 -- 使用new在堆上创建对象数组
50     //在堆上为‘5个Book对象’分配了内存，并为这5个Book对象调用了构造函数
51     Book* books = new Book[5];
52
53     Book* b1 = new Book("算法精解", "Kyle Loudon", 56.2);
54     Book* b2 = new Book("Qt程序设计", "Pulat", 10.2);
55
56     books[0] = *b1; //
57     books[1] = *b2;
58
59     cout << "---- delete b1 ----" << endl;
60     delete b1;
61     cout << "---- delete b2 ----" << endl;
62     delete b2;
63
64     cout << "---- delete []books ----" << endl;
65     delete []books;
66
67     return 0;
68 };