OFF-TOPIC: Algol 60 guru required

[Hiisi]

Dear All!
Sorry for this off-topic, but I could not see any solution to my 
problem. I'm trying to transform old Algol 60 program to C++. I can 
understand every syntax of it except this construction:
D(N+1):=N(N+2):=0.0;

Variables types:
N - INTEGER
D - REAL ARRAY
What is it? How to represent in C++? Hope on this list there's people, 
who could remember that from the time...
Thanks in advance!
--
Hiisi.
Registered Linux User #487982. Be counted at: http://counter.li.org/