把类成员改成指针_如果类中存在管理其他类对象的指针，通过析构函数释放它们...

C.33: If a class has an owning pointer member, define a destructor

C.33:如果类包含拥有所有权的指针成员，定义析构函数Reason(原因)
An owned object must be deleted upon destruction of the object that owns it.从属对象必须通过拥有该对象的所有者类的析构函数销毁。

Example(示例)
A pointer member may represent a resource.A T* should not do so, but in older code, that's common. Consider a T* a possible owner and therefore suspect.指针成员可能用于表达某个资源。T*不应该这么做，但是在旧一些的代码中，这种做法很常见。考虑到T*作为所有者使用的可能性，并确认。

templateclass Smart_ptr {    T* p;   // BAD: vague about ownership of *p    // ...public:    // ... no user-defined default operations ...};void use(Smart_ptr p1){    // error: p2.p leaked (if not nullptr and not owned by some other code)    auto p2 = p1;}

Note that if you define a destructor, you must define or delete all default operations:注意：一旦定义了析构函数，就必须定义或者禁止所有的默认操作。

译者注：这里的默认操作指的是默认构造函数，拷贝/移动构造函数，拷贝/移动运算符和析构函数。

templateclass Smart_ptr2 {    T* p;   // BAD: vague about ownership of *p    // ...public:    // ... no user-defined copy operations ...    ~Smart_ptr2() { delete p; }  // p is an owner!};void use(Smart_ptr2 p1){    auto p2 = p1;   // error: double deletion}

The default copy operation will just copy the p1.p into p2.p leading to a double destruction of p1.p. Be explicit about ownership:默认拷贝操作只是将p1.p的值赋给p2.p(不包含其指向对象的拷贝)，这会导致p1.p的双重析构。明确所有权：

templateclass Smart_ptr3 {    owner p;   // OK: explicit about ownership of *p    // ...public:    // ...    // ... copy and move operations ...    ~Smart_ptr3() { delete p; }};void use(Smart_ptr3 p1){    auto p2 = p1;   // OK: no double deletion}

译者注：实际上并不是改变p的类型为owner就可以解决问题的。注意这段代码通过注释实现了拷贝和移动操作，而前一段代码没有。

Note(注意)

Often the simplest way to get a destructor is to replace the pointer with a smart pointer (e.g., std::unique_ptr) and let the compiler arrange for proper destruction to be done implicitly.一般来说，得到析构函数最简单的方式是将指针换成智能指针(例如std::unique_ptr)并且让编译器提供适当的隐式执行的析构动作。

Note(注意)

Why not just require all owning pointers to be "smart pointers"? That would sometimes require non-trivial code changes and may affect ABIs.为什么不简单地要求所有的所有者指针都变成“智能指针”？因为那样做有时会引起重大的代码变更并且影响二进制接口。

Enforcement(实施建议)