C/C++ vs Pascal

[DarknessX]

Hmmmm, ok. So basically, everything between C/C++ and pascal are nearly identical, except with different syntax, and more/less support available. So technically, anything possible with C/C++ is possible with Pascal?

Thats good to know... It means I don't need to go in-depth on learning C/C++.

[Chebmaster]

So basically, everything between C/C++ and pascal are nearly identical, [...] So technically, anything possible with C/C++ is possible with Pascal?

No.
They are *mostly* the same, but there are things you can do with C that you cannot with Pascal, and vice versa.
Of course, this relates to some pretty advanced stuff, you should be quite experienced in programming to get grip of it.

C has multiple inheritance and tons of other techniques (perverted IMO) you can't easily replicate in Pascal. Also, C has generics and Pascal doesn't (yet). I cannot be of much help here because I'm not familiar with C/C++ myself.

Pascal has metaclasses - a unique feature you won't find in C++. So, for example, my persistency system would be impossible to create with C++.
Metaclasses are quite powerful feature, allowing to decide created object's type at runtime in a very easy and elegant manner. Metaclasses also allow you to write, for example, methods for class to clone itself that will work correctly with all its descendants:

type
  TFrog = class
    constructor RibbitCreate; virtual;
    function OneMore: TFrog;
  end;
  CFrog = class of TFrog;

  TToad = class(TFrog);
  ...

  function TFrog.OneMore: TFrog;
  begin
    Result:=CFrog(Self.ClassType).RibbitCreate;
      //Typecast to CFrog is required here because ClassType() returns TClass,
      //  but TClass doesn't have the RibbitCreate constructor 
  end;

If you call TToad's OneMore you will get TToad, not TFrog, despite the fact that the method is inherited from TFrog unchanged.

AFAIK, you can't do such things in C.

[dmantione]

Why such advanced things? One can give much more practical examples, units for example.

I.e. the following isn't possible in C:

[pascal]
procedure write(lmy_linked_list;var f:file);

begin
if l<>nil then
begin
system.write(f,l^.data);
write(l^.next);
end;
end;
[/pascal]

Summing it up, in C you are constantly evading already existing identifiers. In Pascal, hakuna matata!

[Bijo]

I'm no specialist or professional, but I've had a little share of C, C++ and Pascal (but not Object Pascal).

To me it's those little things like ranges or subranges like 0..17 or something like that which -- as I remember -- cannot be done in C or C++.

Or what about...
[pascal]
with Thing do begin
value1 := 7;
value2 := 10;
value3 := 1;
value4 := 2;
value5 := 344332;
{etcetera}
end;
[/pascal]
...that instead of...
[pascal]
Thing.value1 := 7;
Thing.value2 := 10;
Thing.value3 := 1;
Thing.value4 := 2;
Thing.value5 := 344332;
{etcetera}
[/pascal]

If I recall correctly a similar thing -- the use of with-do -- cannot be done in C or C++. It's just a beautiful simple elegant touch that is effective as I see it.

[Robert Kosek]

You can actually use the with-do in functions ... :twisted:

[pascal]with TObject.Create do begin
func_param1 := 'abc';
AOwner := Form1;
end;[/pascal]

In C/C++ (AFAIK) you cannot do:[pascal]// Read until INI-File style comments.
repeat
inc(i);
until (inStr[i+1] in [#13,#10,#0,';']);[/pascal]

In fact, I even coded a semi-complete 3 byte (YES!) variant system for a variant stack for scripting! In four hours!!

I work in ANSI-C for CGI scripting for a web interface as a part of my work. It's ugly, instable, requires work-a-rounds, and really hard to keep up to date without breaking anything. I could rewrite our whole interface in Pascal -- ignoring the time to get adjusted to Pascal CGI -- in less than half the time it has taken them to add pages and maintain the present beast.

[Bijo]

Heh heh, what a great topic, people. I rejoice when I notice criticism (or the likes) on C/C++, heh heh


DarknessX, check out this link: http://www.zel.org/oberon/fromctoo.htm : it's about Oberon-2 and such and C and C++. It might prove you useful.

[Setharian]

[pascal]procedure GetRawData(const F: Single): Integer; inline;
var
I: Integer absolute F;
begin
// returns binary representation of a float in an integer
Result := I;
end;[/pascal]
absolute keyword, I am not aware of an equivalent in C....aliasing one variable over another is considered hacky, but sometimes it has its uses

also you forgot about the best, built-in support for strings and dynamic arrays with reference counting....something C(++) can only dream of (it is possible by using smart pointers in C++ but it's ugly and not used)...next extremely fast compilers compared to C++ ones (C ones can be quite fast because it's actually a lot cleaner than the monster C++ is)...then support for method pointers (function(Args): ResultType of object) which is also missing in C(++)....sets, subrange types (already mentioned), interfaces (those can be simulated with abstract base classes combined with multiple inheritance in C++)....and I guess one may find even more things which are better in Object Pascal than in C(++)....

sometimes I wish OP would allow some equivalent for C's bitfields in structures with automatic shifting/masking to get the correct results on set/get possibly enhanced by OP's range checks....that would be cool
class allocation on the stack is also a nice feature, on the other and it makes C++ classes just a bit more than structs and forces you to use pointers everywhere (explicitly) while in OP class instances are implicitly pointers and save you a lot of headaches.....

all in all I'd say OP has more features which C(++) does not than C(++) has and OP doesn't have...that combined with a much less confusing syntax and easily readable code makes it a perfect choice for development....

[dmantione]

sometimes I wish OP would allow some equivalent for C's bitfields in structures with automatic shifting/masking to get the correct results on set/get possibly enhanced by OP's range checks....that would be cool

✓ Check :twisted:

Try {$bitpacking on}, then declare a packed array or record.

[JernejL]

Try {$bitpacking on}, then declare a packed array or record.

which compiler supports that?

[Setharian]

no idea what that directive does....it would seem it reduces sizes of structures to a bare minimum but since I know no syntax with which I could declare fields with size of X bits I'm not sure how I can I make use of it...it isn't documented in the online documentation...besides I'm using Delphi IDE with DCC