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Archive for the ‘pascal’ tag

By coding a Record

Memory-representation

Memory representation with record

We commonly think to a record like something to be registered or annotated; musical, medical and data recording, and so on.
But structurally… what is a record?

Definition is so simple to result boring: a record is a structure (collection) of different nature data.

In the previous article we saw an important structure called array: a collection of homogeneous data.
An array can host only one kind of data per time: integer numbers or characters or arrays again…

 

Records offer one more degree of liberty: they can contain integers and chars and arrays… and records as well!

So a sport record is a possible collection of: first and last name (chars or strings), kind of sport (chars or strings) and the performance (typically a number).


Performance is what we commonly intend with sport record, but this is an example of metonymy (yes, we are poets too :) ). Read the rest of this entry »

Written by admin

November 30th, 2011 at 11:17 am

Variables looping and grouping

Memory-Representation

RAM Memory Representation

In prolog of the previous article we talked about the possibility to create more abstact levels of information once we’re sure about simpler ones.
We’ll touch with hands how to group variables into structures containing them.
To make things easier please refer to picture, where RAM memory scheme is represented in the simplest logical view.

Every colored box is a location where to put data and as well it has a label assigned by operating system on its startup: progressive numeration is enough for our goals.
It doesn’t matter if first box matches the effective first memory location: here we just need to think these boxes contiguous.


What happens when a compiler meets a variable declaration? Read the rest of this entry »

Written by riccardo

November 23rd, 2011 at 10:58 am

Strange Types Circulating (in code)

0-and-1

0 and 1 communicating

In a world of 0 and 1 bits the necessity to create a convention for communications rises up immediately.
They are the logical minimum set to create information (and the best one, as having been demonstrated), through possible variations between them. In absolute they’re pure data.

Is it enough? certainly it isn’t; we need at least a convention thanks to which creating an amount of interchangeable informations.

By basing on these last ones, we create again other more abstract new informations, and so on.

We’re trying to summarize in few words a process that took many decades of years to assume a definitive common physiognomy, in the effort to bring computer science closer to human vision and vice versa: in a way you don’t have to worry about what is happening under the hood… if you don’t want!
But if you did? Read the rest of this entry »

Written by riccardo

November 15th, 2011 at 11:28 pm