Re: Newbie question

[Michal Nowak <vinnie@inetia.pl>]

On 01-12-24 at 13:52 Jasbinder S Uppal wrote:

>Hi, I've been subscribed to this news group for a long time (ok, when I
>first started using Ada, about 2 months ago!), but this is the first time
>I've actually had problems with the language and well, I was wondering if
>you guys can help me.

Welcome newbie, from another newbie :-))

>I've got this assignment for university that I have to do, and I am having
>problems with the first bit (Not a good sign, is it....).
>I've got a data file, which contains a line of data for a vehicle, and on
>the line, it gives a place name, a registration number, and the time that
>the car goes onto a motorway. A typical line is as follows....
>
>Barnsley    A123       22    15    40
>....
>....
>Where Barnsley is the place, A123 is the Registration number, and 22  15
>40 is the time (22:15:40). I've managed to get the Place name (using
>characters) and the registration number (using Strings), and putting it
>into
>a record, but I am unsure as to what to use for the time. I could (I think)
>use characters, but I need to manipulate the times later on in the program
>(which could be done by having the time as an integer), but because there
>are blanks in between the numbers, I am unsure as to how I can do this.
>Help
>me please....
>
>I appreciate any help given.
>
>Thanks.

As I said, I'm newbie also, but maybe this will be helpful.

Generally speaking, you may do like this:

...
Read place name,
Read registration number,
skip spaces,
read hour,
skip spaces,
read minute,
skip spces,
read second.
...

However, reading character after character from disc file is
inefficient way. My proposal is to read whole line into a string.
I assume, that hours, minutes and seconds are two digits
numbers (so the hour 7AM is presented as 07).
If no, you will have a bit more work.

Extract place name from string
Extract registration number
Skip Spaces
   You should know on which position in the string you are
   after skipping spaces. Let's call it Current_Position and
   let Whole_Line be of type String and consist line from
   input file.
   Hour := Integer'Value (Whole_Line(Current_Position .. Current'Position + 2) );

   Hour is of type Integer. It does not has to be predefined
   Integer. You may do something like this:
   type Hour_Type is range 0 .. 23; --this is declaration of
                                    --integer type
   Hour : Hour_Type;
   However, if you declare Hour_Type as a distinct type, you will
   have to cast result of Integer'Value to Hour_Type before assigning
   it to Hour:

   Hour := Hour_Type (Integer'Value (
                        Whole_Line(Current_Position .. Current'Position + 2) )
                     );

Do the same for minutes and seconds.
Exception handling is your task to do.

I'm not sure if this is very elegant way of doing it, but as
I said, I'm still a newbie.

I hope this will help you in some way.
Happy Ada programming,
-Mike
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