how to add vector matrix

[Laus]

long xcc[]={0,0,1,1};
long ycc[]={1,1,1,1};
int out[];

out[]=ycc[]+xcc[];
out[]=={1,1,1,1,0,0,1,1}; // I need this output, how to get this?

[Ttelmah]

First thing is you need to give 'out' a size. Your initialised arrays are given
sizes, because you initialise them, However the uninitialised array won't
be given storage.

Then what you show is not standard matrix addition. The addition of
xcc, and ycc would give {1,1,2,2}.

There is also an issue, in that your source values are declared as 'long',
so could be up to 65535, but your destination array is only declared as
'int', so could only hold values up to 255.
You seem to be wanting just the stored vals concatenated into the target.
Concatenation: