unsigned integer overflow behaviour

[bartek]

Hello,

Please help me with the obvious...

Does the standard say anything about integer overflow? Does it result in
implementation defined behaviour?

Would the following code snippet result in '0' being displayed on all
implementations?

unsigned x(std::numeric_limits<unsigned>::max());
std::cout << ++x << std::endl;

Cheers,
b

 

[Ron Natalie]

Would the following code snippet result in '0' being displayed on all
implementations?

unsigned x(std::numeric_limits<unsigned>::max());
std::cout << ++x << std::endl;

Yes, It is required that unsigned variables roll over from their max value to zero.

3.9.1/4
Unsigned integers, declared unsigned, shall obey the laws of arithmetic modulo 2n where n is the number

of bits in the value representation of that particular size of integer.

 

[Ron Natalie]

Yes, It is required that unsigned variables roll over from their max value to zero.

3.9.1/4
Unsigned integers, declared unsigned, shall obey the laws of arithmetic modulo 2n where n is the number

of bits in the value representation of that particular size of integer.

The thing after modulo is supposed to be 2 raised to the nth power. The superscript got lost in the
cut and pasting.

 

[bartek]

(...)

The thing after modulo is supposed to be 2 raised to the nth power.
The superscript got lost in the cut and pasting.

Thank you. I did extrapolate that though.

Cheers,
b