c++ - C++创建对相同数据进行操作的子 vector

Question

您好，我有一个 vector :

vector<int> myCuteVector {1,2,3,4};

现在，我想以一种方式创建子 vector ，使其包含myCuteVector中的2个第一个元素，以便在修改子 vector 元素之后，myCuteVector的元素也将更改。

伪代码:

vector<int> myCuteVector {1,2,3,4};
vector<int> myCuteSubVector = myCuteVector[0:2];
myCuteSubVector[0] = 5;
printf("%d", myCuteVector[0]) //would print also 5;

有可能实现吗？

Answer 1

您可以使用 std::reference_wrapper 做到这一点。看起来像:

int main()
{
    std::vector<int> myCuteVector {1,2,3,4};
    std::vector<std::reference_wrapper<int>> myCuteSubVector{myCuteVector.begin(), myCuteVector.begin() + 2};
    myCuteSubVector[0].get() = 5; // use get() to get a reference
    printf("%d", myCuteVector[0]); //will print 5;
}

或者您可以直接使用迭代器，例如

int main()
{
    std::vector<int> myCuteVector {1,2,3,4};
    std::vector<std::vector<int>::iterator> myCuteSubVector{myCuteVector.begin(), myCuteVector.begin() + 1};
    // it is important to note that in the constructor above we are building a list of
    // iterators, not using the range constructor like the first example
    *myCuteSubVector[0] = 5; // use * to get a reference
    printf("%d", myCuteVector[0]); //will print 5;
}