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Accepted
Agustin A.H.
Asked: 2022-08-06 06:25:15 +0800 CST 2022-08-06 06:25:15 +0800 CST

What happens if I don't assign a value to a variable and print it?

  • 772

I know this may sound like a very basic/dumb question. But to put an example in Pascal,

Program prueba ;
var
  a : integer ;
begin
  write(a) ;
end.

For example, if I were asked what the write(a) prints on the screen, what would it print?

pascal

1 Answers

  1. Best Answer

    The documentation says in perfect Spanish

    By default, simple variables in Pascal are not initialized after their declaration. Any assumption that they contain 0 or any other default value is erroneous: They can contain rubbish.

    Which more or less says that Pascal doesn't initialize them when declaring them and they can contain anything. Thus, it is healthy to declare and initialize them before using them for the first time, taking into account the corresponding scope .

    They also indicate that there are two exceptions to this behavior:

    • Managed types are an exception to this rule: They are always initialized to a default value: in general, this means setting the reference count to zero or setting the pointer to Nil
    • Global variables are initialized to the equivalent of zero.

    And remember that they are always initialized, they occupy space in memory only when the program reaches the corresponding scope.

    P.S. It's not a silly question. It is, in fact, very important and asking these kinds of questions is what prevents future bugs. In general, initializing and checking the initial value is good practice (except in cases where certain data types ensure a useful default value, thus saving you the trouble of getting everything ready to work). But to do this with certainty there is always to review the documentation).

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