Question

I have a C# method that use “params” modifier for a 2-dimentions array.

/// <summary>
///   Combine vectors horizontally.
/// </summary>
/// 
public static T[] Concatenate<T>(params T[][] vectors)
{
    int size = 0;
    for (int i = 0; i < vectors.Length; i++)
        size += vectors[i].Length;

    T[] r = new T[size];

    int c = 0;
    for (int i = 0; i < vectors.Length; i++)
        for (int j = 0; j < vectors[i].Length; j++)
            r[c++] = vectors[i][j];

    return r;
}

I convert it to Java like this:

{
    int size = 0;
    for (int i = 0; i < vectors.length; i++)
    {
        size += vectors[i].;
    }

    T[] r =(T[]) Array.newInstance(vectors[0][0].getClass(), size);

    int c = 0;
    for (int i = 0; i < vectors.length; i++)
    {
        for (int j = 0; j < vectors[i].length; j++)
        {
                r[c++] = vectors[i][j];
        }
    }

    return r;
}

But it seems to be wrong. Solution doesn’t work.
Please someone tell me the right way.
Thanks a lot.

Answer 1

In Java you use ... instead of params, as is explained here

So you declare your method like this (note the loss of one []):

public static T[] Concatenate<T>(T[]...vectors)