Re: Calculator and Operator Precedence

[Stephen Leake <stephen.a.leake.1@gsfc.nasa.gov>]

jon <jkjw@brighton.ac.uk> writes:

> i ve built a basic calculator which asks user for expression using a
> console.
> 
> eg
> 
> Enter expression : 1 + 2 + 3 * 4
> 
> now i need to make it so it can handle Operator Precendence
> 
> whats the best way of doing this ? Arrays ?

You need a tree structure, with operators at the nodes and operands at
the leaves.

You can implement a tree using arrays, or linked lists, or many other
things. Or you can use an existing package from on of the Ada
libraries available. See http://www.adapower.com/reuse/index.html

Hmm, I just noticed my library isn't there; I'll have to fix that :).
See http://users.erols.com/leakstan/Stephe/Ada/sal.html

-- 
-- Stephe