nitems

/*
 *  call-seq:
 *     array.nitems -> int
 *  
 *  Returns the number of non-<code>nil</code> elements in _self_.
 *  May be zero.
 *     
 *     [ 1, nil, 3, nil, 5 ].nitems   #=> 3
 */

static VALUE
rb_ary_nitems(ary)
    VALUE ary;
{
    long n = 0;
    VALUE *p, *pend;

    p = RARRAY(ary)->ptr;
    pend = p + RARRAY(ary)->len;

    while (p < pend) {
        if (!NIL_P(*p)) n++;
        p++;
    }
    return LONG2NUM(n);
}