[R] modifying arrays within functions

[Konrad BLOCHER]

Hi,

I'm preetty new to R and seem to be having difficulties with writing a
function that would change an array and keep the change after the function
finishes its work.

in other words

I have an array of 1's    X<-array(1,dim=c(2,2))

I want to add a number to X[1,1] by means of a function called addition.
What I am writing is:   addition<-function(a){X[1,1]=X[1,1}+a}
but it doesn't seem to work

Any ideas? Please? :)

Thanks

KB