Re: Ada Examples and Problems

["chris.danx" <chris.danx@ntlworld.com>]

Hi folks,

I rewrote the part of the example that reads data from the file.  It works
now but not as i intended.

The program was supposed to read in

    a) owners first
    b) dogs second

    X) then display the output

as an example of non sequential Stream IO.  This means the problem lies with
the read_owners and the read_dogs routines.

Each owner record is followed by a dog record which is followed by a owner
record and so on.

There are five of each, meaning ten records in total.

I got the sizes of each record from the program

dog_type:    56 bytes
owner_type: 41 bytes

starting at 1, i read the first owner.
this means we're now at 42 after the first read.


Add size of dog_type in stream elements, this is byte for GNAT.
this means we're now at 56+42 = 98

add 1
we're now at 99

read next owner.


That's the theory.  The reality is different.

The reads occur at

        1
      97
    193
    289
    385
    481

Which i don't understand.

Does anyone have any ideas?


Thanks,
Chris Campbell

p.s. I got the program to work by doing a read of owner then dog 5 times.  I
wanted to demonstrate non-sequential access and this is the opposite.