Q***5
发帖数: 994 | 1 I'm working through D. Rajan's Challenges with C++, and have some questions | n******t
发帖数: 4406 | 2 The definition appears at line X, makes the i available to the whole switch
control statement and you initialized it, C++ does not allow this to happen,
because other wise you could use some variable without actually
initializing it.
This type of questions is really pedantic, a well-trained programmer won't
really come to situations like this.
questions
【在 Q***5 的大作中提到】
: I'm working through D. Rajan's Challenges with C++, and have some questions
| Q***5
发帖数: 994 | 3 Thanks. But I still don't quite understand your point about initialization.
For example, if we change line X to
int i; i = 10;
to change initialization to assignment, is that allowed?
or no declaration of variable inside a switch at all?
switch
happen,
【在 n******t 的大作中提到】
: The definition appears at line X, makes the i available to the whole switch
: control statement and you initialized it, C++ does not allow this to happen,
: because other wise you could use some variable without actually
: initializing it.
: This type of questions is really pedantic, a well-trained programmer won't
: really come to situations like this.
:
: questions
| n******t
发帖数: 4406 | 4
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This is allowed. Because now you define a variable WITHOUT initializing it.
So C++ believes that you will do the assignment yourself. Just like those
simple
case with out switch control.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
It is allowed, but a declaration of variable with initializer while could
be potentially jumped over, is not allowed.
【在 Q***5 的大作中提到】
: Thanks. But I still don't quite understand your point about initialization.
: For example, if we change line X to
: int i; i = 10;
: to change initialization to assignment, is that allowed?
: or no declaration of variable inside a switch at all?
:
: switch
: happen,
| Q***5
发帖数: 994 | 5 Got you. Thanks.
【在 n******t 的大作中提到】
:
: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
: This is allowed. Because now you define a variable WITHOUT initializing it.
: So C++ believes that you will do the assignment yourself. Just like those
: simple
: case with out switch control.
: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
: It is allowed, but a declaration of variable with initializer while could
: be potentially jumped over, is not allowed.
|
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