C＃数组到C ++向量

Question

What is the equivalent from C# to C++ of doing this:

int[n][num] card;
someFunction(card[0]);


someFunction(int[] card)
{
    ....
}

Using vectors in C++

---

Also

Is this code in C++:

std::vector< std::vector <int> > a(numA, vector<int>());

equivalent to this code in C# ?:

int[][] a = new int[numA][];

If it is not, please tell me how it should be. Thanks.

Answer 1

I don't know C# but this looks right

std::vector< std::vector<int> > card;
someFunction(card[0]);


void someFunction(const std::vector<int>& card)
{
    ....
}

Use & to indicate that you are passing the vector by reference to avoid the overhead of copying the vector itself. If you want someFunction to modify the vector then drop the const .

Your other code looks OK too.

Answer 2

vector<vector<int> > card(n, std::vector<int>(num));
someFunction(card[0]);

someFunction(vector<int> vec)
{
    ....
}

This:

std::vector< std::vector <int> > a(numA, vector<int>());

and simpler

std::vector< std::vector <int> > a(numA);

are C++ jagged arrays equivalent to:

int[][] a = new int[numA][];