Re: Ada for 1st year students

[Mike H <newsreader@ada-augusta.demon.co.uk.INVALID>]

In message 
<9955de2c-f74a-4c2b-b513-56c130a5f1ee@k16g2000hsf.googlegroups.com>, 
amado.alves@gmail.com writes
>And for starting they will even use a package that predeclares
>variables I, J, K, L, M as integers, X, Y, Z as reals, etc. That's my
>approach anyway, logic first, types later. They just include the
>package and voila, by magic, all the variables in the pseudocode are
>there for usage in the same way. Later I will explain this magic, by
>looking inside the package, and then they will redo their programs
>sans that package.

I really do think that types are fundamental to good Ada code. When I 
taught Ada I started with types. Before they even saw a line of Ada code 
I would get class groups discussing 'time' and 'duration'.
- are time and duration interchangeable?
- if you subtract a time from a time, what do you get?
- what about other operations on a pair of time variables?
- what about operations on duration variables
- are there any sensible multiplication or division operations

Usually the discussions got quite heated and that was the object of the 
exercise! By the time they were called to order, their minds were much 
more open to the concept of strict typing (especially those who had had 
other programming experience such as C).

I then gave some simple examples and exercises using a package 
declaration containing pre-declared integers, minutes and time (time as 
minutes since some arbitrary event) to demonstrate how errors at compile 
can be 'friendly'! My 'magic' was to follow that up by showing them the 
package body code.
-- 
Mike Hopkins