Challenge: Function that prints a n big tree

Write a function that prints an n big tree, e.g. for n=5:

     * 
    * * 
   * * * 
  * * * * 
 * * * * * 
    | |

Here is what I came up with in C:

N,i;a(n){for(i=N=N?N:n+2;i--;printf(i?"* "+(N-n-1<i):--n?"\n":"\n%*s",N,"| |"));n&&a(n);}

// the invocation isn't part of the golf:
main(){a(5);}

PS: Code blocks currently wrap around when they are too long, I've already submitted a patch to make them scroll horizontally instead.