print a 2d vector in c++
// A recursive function able to print a vector
// of an arbitrary amount of dimensions.
template<typename T>
static void show(T vec)
{
std::cout << vec;
}
template<typename T>
static void show(std::vector<T> vec)
{
int size = vec.size();
if (size <= 0) {
std::cout << "invalid vector";
return;
}
std::cout << '{';
for (int l = 0; l < size - 1; l++) {
show(vec[l]);
std::cout << ',';
}
show(vec[size - 1]);
std::cout << '}';
}