Pushing an array into a vector

Question

I\'ve a 2d array, say A[2][3]={{1,2,3},{4,5,6}}; and I want to push it into a 2D vector(vector of vectors). I know you can use two for loops to pus

Answer 1

This is a little tricky, but you could use template recursion to help you in having the assignment done almost completely at compile-time. I understand that's not exactly what you are looking for, but I think it's worthwhile :-)

Here's the code:

#include 

using namespace std;

typedef vector > vector2d;

template
struct v_copy {
    static void copy(vector2d& v, int(&a)[M][N])
    {
        v[K - 1].assign(a[K - 1], a[K - 1] + N);
        v_copy::copy(v, a);
    }
};

template
struct v_copy<1, M, N> {
    static void copy(vector2d& v, int(&a)[M][N])
    {
        v[0].assign(a[0], a[0] + N);
    }
};

template
void copy_2d(vector2d& v, int(&a)[M][N])
{
    v_copy::copy(v, a);
}

int main()
{
    int A[2][3] = {{0, 1, 2}, {10, 11, 12}};
    vector2d vector(2);

    copy_2d(vector, A);
}

it needed a struct because in C++ you can't do partial specialization of functions. BTW , compiling it with gcc version 4.5.0, this code produces the same assembly as

vector[1].assign(A[1], A[1] + 3);
vector[0].assign(A[0], A[0] + 3);

It should not be very hard to have it compile with different types of 2-dimensions arrays.