C ++：交换两个不同向量的两个元素

Question

std::vector<int> v1 = {1,3,6};
std::vector<int> v2 = {2,4,7};

swap v1[m] with v2[n]

instead of copying and then just overwriting both elements

I tried

std::swap(v1.begin() + m, v2.begin() + n);

but that didn't work

Answer 1

std::swap需要引用，而不是迭代器：

std::swap(v1[m], v2[n]);

Answer 2

您对此太想了-您只需要：

std::swap(  v1[m],  v2[n] );

Answer 3

From your example it looks like what you need might be iter_swap

As per your example:

std::iter_swap(v1.begin() + m, v2.begin() + n);

Should work for you.

Answer 4

You can of course use iterators with swap :

std::swap(*(v1.begin() + m), *(v2.begin() + n));

or

std::swap(v1[m], v2[n]);

or

std::swap(v1.at(m), v2.at(n));