T*
to indicate a position (only)That's what pointers are good for. Returning a T*
to transfer ownership is a misuse.
这是指针的强项。使用T*返回所有权是错误的用法。
Node* find(Node* t, const string& s) // find s in a binary tree of Nodes
{
if (!t || t->name == s) return t;
if ((auto p = find(t->left, s))) return p;
if ((auto p = find(t->right, s))) return p;
return nullptr;
}
If it isn't the nullptr
, the pointer returned by find
indicates a Node
holding s
. Importantly, that does not imply a transfer of ownership of the pointed-to object to the caller.
如果返回值不为nullptr,则find返回的指针表示持有s的Node。重要的是,它不包含向调用者传递指针所指向的对象的所有权的含义。
Positions can also be transferred by iterators, indices, and references. A reference is often a superior alternative to a pointer if there is no need to use nullptr
or if the object referred to should not change.
位置也可以通过迭代器,索引和引用传递。如果不需要使用nullptr或者对象不希望被修改,引用通常是比指针更好的选择。
Do not return a pointer to something that is not in the caller's scope; see F.43.
不要返回指向不属于调用者范围的某物的指针。
See also: discussion of dangling pointer prevention
参见:关于防止悬空指针的讨论。
delete
, std::free()
, etc. applied to a plain T*
. Only owners should be deleted.
标示运用在直接指针上的delete,std::free()等操作。只用所有者才可以删除。
new
, malloc()
, etc. assigned to a plain T*
. Only owners should be responsible for deletion.
标记将结果分配个直接指针的new,malloc()等处理。只有所有者才有销毁的责任。觉得本文有帮助?请分享给更多人。
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