所以,如果我有一个班级
class Item {
public:
Item(int key, int value):key(key), value(value) {}
int GetValue() {
return value;
}
private:
int key;
int value;
}
如果我在堆上创建一个Item对象:
Item *item = new Item(1, 2);
是否可以将指针指向此对象的value成员?
例如,我有另一个类的另一个方法
int* GetValue(int k) {
Item* item = ...; // It finds the pointer to an Item object with key k that was created before.
// Is there anyway I can return the pointer to the value member of this item?
// Something like:
return &(item->GetValue()); // This won't compile because item->GetValue() is a r-value. Is there any alternative way to walk around?
}
答案 0 :(得分:0)
尝试将这些代码添加到您的代码中。
template <class Tag, typename Tag::type Value>
struct Getter
{
friend typename Tag::type get(Tag) {
return Value;
}
};
struct Tag_item {
typedef int Item::*type;
friend type get(Tag_item);
};
int* GetValue(int k) {
static Item item(13, 14);
// std::cout << item.GetValue() << std::endl; // This line to test output.
return &(item.*get(Tag_item())); // If pItem is pointer then pItem->*get(Tag_item())
}
template struct Getter<Tag_item, &Item::value>;
请参阅http://coliru.stacked-crooked.com/a/3be5b80e848650c5
上的演示http://bloglitb.blogspot.com/2011/12/access-to-private-members-safer.html
致Johannes Schaub - litb