Am I an idiot?

[Kevin Grigorenko]

That's a rethorical question. But shouldn't this statement store the value
of three in the variable a:

#include <iostream>

int main()
{
int a = 1 & 2;
if(a & 1)
{
std::cout << "One " << std::endl;
}
if(a & 2)
{
std::cout << "Two " << std::endl;
}
return 0;
}

I'm trying to use bit-masking to pass around flags with an integer, and then
check them with if( integer & flagX )

What is going on?

Thanks a lot for your time,
Kevin Grigorenko

[David Fisher]

"Andrey Tarasevich" <an************ **@hotmail.com> wrote:

Positive integral values are represented in the same way in all binary
formats supported by C/C++ specifications. In other words, 1 is
guaranteed to be '0..001' and 2 is guaranteed to be '0..010'.

Note, that "bits" that are mentioned in the language specification are
language-level abstractions. The actual underlying hardware might even
be non-binary (ternary, for example) and have nothing that can be
regarded as physical "bits".

OK, my mistake ...

Thanks for the info :-)

David F

[Tron Thomas]

It looks like you used the wrong logical operator to initialize the
variable "a".

If you logically AND the value 1 with the value 2, the result is zero.

You probably want to OR the two values together.

Replace:
int a = 1 & 2;

With:
int a = 1 | 2;

Kevin Grigorenko wrote:

That's a rethorical question. But shouldn't this statement store the value
of three in the variable a:

#include <iostream>

int main()
{
int a = 1 & 2;
if(a & 1)
{
std::cout << "One " << std::endl;
}
if(a & 2)
{
std::cout << "Two " << std::endl;
}
return 0;
}

I'm trying to use bit-masking to pass around flags with an integer, and then
check them with if( integer & flagX )

What is going on?

Thanks a lot for your time,
Kevin Grigorenko