c++ 成员对象的析构时机
时间: 2024-04-22 15:26:19 浏览: 14
C++中的成员对象的析构时机取决于它们在类中的声明方式。有两种主要的情况需要考虑:
1. 对象作为类的成员变量:当包含该成员对象的类的析构函数被调用时,成员对象的析构函数也会被自动调用。成员对象的析构顺序与它们在类中声明的顺序相反。
例如,考虑以下代码:
```cpp
class Member {
public:
Member() {
cout << "Member constructed" << endl;
}
~Member() {
cout << "Member destructed" << endl;
}
};
class MyClass {
private:
Member member1;
Member member2;
public:
MyClass() {
cout << "MyClass constructed" << endl;
}
~MyClass() {
cout << "MyClass destructed" << endl;
}
};
```
当创建一个`MyClass`对象并销毁它时,输出将是:
```
Member constructed
Member constructed
MyClass constructed
MyClass destructed
Member destructed
Member destructed
```
2. 对象作为类的指针成员:对于指向动态分配的对象的指针成员,析构时机稍有不同。在对象的析构函数中,你需要手动释放指针所指向的内存,并在适当的时候调用`delete`操作符。这通常在类的析构函数中完成。
例如,考虑以下代码:
```cpp
class Member {
public:
Member() {
cout << "Member constructed" << endl;
}
~Member() {
cout << "Member destructed" << endl;
}
};
class MyClass {
private:
Member* memberPtr;
public:
MyClass() {
memberPtr = new Member();
cout << "MyClass constructed" << endl;
}
~MyClass() {
delete memberPtr;
cout << "MyClass destructed" << endl;
}
};
```
当创建一个`MyClass`对象并销毁它时,输出将是:
```
Member constructed
MyClass constructed
MyClass destructed
Member destructed
```
请注意,如果你在构造函数中使用了`new`操作符,你应该在析构函数中使用`delete`操作符来释放相应的内存。这样可以确保对象被正确地销毁,避免内存泄漏。