Assigning double constant to integer types

[dev]

when i do int x=2.2;

Is this behaviour undefined.?
K & R says that it may draw a warning but it is not illegal....

now one more point--
Can a legal behaviour be undefined?
or vice versa,I mean that can a undefined behavior be illegal?

 

[Michael Tsang]

when i do int x=2.2;

Is this behaviour undefined.?
K & R says that it may draw a warning but it is not illegal....

now one more point--
Can a legal behaviour be undefined?
or vice versa,I mean that can a undefined behavior be illegal?

This is completely legal:
2.2 is implicitly converted to int
Use -Wconversion in gcc to catch these type of conversions.

 

[Eric Sosman]

when i do int x=2.2;

Is this behaviour undefined.?

No.[*] It declares a variable of type `int' named `x',
and initializes it with the value two.

[*] Not from the available context, that is. With enough
additional stuff the behavior could be made undefined: For
example, by putting the line at file scope in one translation
unit, and putting `extern double x;' in another.

K & R says that it may draw a warning but it is not illegal....

now one more point--
Can a legal behaviour be undefined?
or vice versa,I mean that can a undefined behavior be illegal?

Yes, legal behavior can be undefined. That is, many
jurisdictions will not impose legal penalties upon you if
you write code that exhibits undefined behavior. The C
Standard itself does not have the force of law.

(In other words, you need to decide what you mean by
"legal behaviour." Once you've decided that, your question
will probably answer itself.)