How to pass a 2D vector to a function using pass-by-reference C++

Question

struct st
{
    int to, cost;
};

void fun(vector<st>&v1[10])
{
    vector<st>v2[10];
    v1=v2;
}

int main()
{
    vector<st>arr[10];
    fun(arr);
}

I want to pass a 2D vector in a function by reference and swap the vector with another vector in that function. But I am getting error. I don't want to do it with pair vector. I want to use structure here. How to do it?

here is a screenshot of my error messege

Answer 1

One major problem: When passing an array as an argument, what is really passed is a pointer .

It can easily be solved by using std::array instead:

void fun(std::array<std::vector<st>, 10>& v1)
{
    std::array<std::vector<st>, 10> v2;
    // Initialize v2...
    v1 = v2;
}

int main()
{
    std::array<std::vector<st>, 10> arr;
    fun(arr);
}

---

After introducing std::array above, I would rather recommend returning the array instead of passing by reference:

std::array<std::vector<st>, 10> fun()
{
    std::array<std::vector<st>, 10> v2;
    // Initialize v2...
    return v2;
}

int main()
{
    std::array<std::vector<st>, 10> arr = fun();
}