Hi,

I'm trying to figure out the purpose of these operators.
Now, I know what they do. They shift bits either left or right.
But I don't know why would anybody want to do that. I've never seen
anyone using it in his/her code.
Any ideas?

Thanks,
Ben

Ben wrote:
> I'm trying to figure out the purpose of these operators.
> Now, I know what they do. They shift bits either left or right.
> But I don't know why would anybody want to do that. I've never seen
> anyone using it in his/her code.

I think you have seen too little code.

They are used - both for real bit manipulation
stuff and for multiplication and division with
powers of two.

Most CPU's actually implement them in their
native instruction set.


Arne

> They are used - both for real bit manipulation
> stuff and for multiplication and division with
> powers of two.
>
> Most CPU's actually implement them in their
> native instruction set.

In fact that's why we have them.

k = j << 3;

is a lot faster than

k = j * 8;

Ben wrote:
> Hi,
>
> I'm trying to figure out the purpose of these operators.
> Now, I know what they do. They shift bits either left or right.
> But I don't know why would anybody want to do that. I've never seen
> anyone using it in his/her code.
> Any ideas?

it is a tragic mistake that an operator that is tailor made for piping
and adding to lists, is reserved instead for such a trivial, seldom
used operation. If you want to shift bits, better to have a new literal
operator:
bunchOfBits shiftleft 2 ;

-Steve

Maybe you would like to expand on the 'piping and 'adding' bits.

Also, what makes you think that bit-shifting is seldom used?


"Steve Richter" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>
> Ben wrote:
>> Hi,
>>
>> I'm trying to figure out the purpose of these operators.
>> Now, I know what they do. They shift bits either left or right.
>> But I don't know why would anybody want to do that. I've never seen
>> anyone using it in his/her code.
>> Any ideas?
>
> it is a tragic mistake that an operator that is tailor made for piping
> and adding to lists, is reserved instead for such a trivial, seldom
> used operation. If you want to shift bits, better to have a new literal
> operator:
> bunchOfBits shiftleft 2 ;
>
> -Steve
>

Stephany Young wrote:
> Maybe you would like to expand on the 'piping and 'adding' bits.

arrayOfLines << new string( "another line" ) ; // adds to the end
of the array
databaseTable << row ; // adds a row to the database table

the general rule being:
<< adds to something
= replaces the contents of something with something else.

> Also, what makes you think that bit-shifting is seldom used?

I have not used bit shifting for years. If you are looking to multiply
or divide, better to use those operators. ( and the optimized compilers
of today likely bit shift when we multiply by a constant that is a
power of 2. )

-Steve




>
>
> "Steve Richter" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
> >
> > Ben wrote:
> >> Hi,
> >>
> >> I'm trying to figure out the purpose of these operators.
> >> Now, I know what they do. They shift bits either left or right.
> >> But I don't know why would anybody want to do that. I've never seen
> >> anyone using it in his/her code.
> >> Any ideas?
> >
> > it is a tragic mistake that an operator that is tailor made for piping
> > and adding to lists, is reserved instead for such a trivial, seldom
> > used operation. If you want to shift bits, better to have a new literal
> > operator:
> > bunchOfBits shiftleft 2 ;
> >
> > -Steve
> >

> arrayOfLines << new string( "another line" ) ; // adds to the end
> of the array
> databaseTable << row ; // adds a row to the database table
>
> the general rule being:
> << adds to something
> = replaces the contents of something with something else.

And what language might that be defined in?

> I have not used bit shifting for years. If you are looking to multiply

Just because you personally have not used a powerful element of the language
for years, don't assume that other people don't use it regularly.


"Steve Richter" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>
> Stephany Young wrote:
>> Maybe you would like to expand on the 'piping and 'adding' bits.
>
> arrayOfLines << new string( "another line" ) ; // adds to the end
> of the array
> databaseTable << row ; // adds a row to the database table
>
> the general rule being:
> << adds to something
> = replaces the contents of something with something else.
>
>> Also, what makes you think that bit-shifting is seldom used?
>
> I have not used bit shifting for years. If you are looking to multiply
> or divide, better to use those operators. ( and the optimized compilers
> of today likely bit shift when we multiply by a constant that is a
> power of 2. )
>
> -Steve
>
>
>
>
>>
>>
>> "Steve Richter" <(E-Mail Removed)> wrote in message
>> news:(E-Mail Removed)...
>> >
>> > Ben wrote:
>> >> Hi,
>> >>
>> >> I'm trying to figure out the purpose of these operators.
>> >> Now, I know what they do. They shift bits either left or right.
>> >> But I don't know why would anybody want to do that. I've never seen
>> >> anyone using it in his/her code.
>> >> Any ideas?
>> >
>> > it is a tragic mistake that an operator that is tailor made for piping
>> > and adding to lists, is reserved instead for such a trivial, seldom
>> > used operation. If you want to shift bits, better to have a new literal
>> > operator:
>> > bunchOfBits shiftleft 2 ;
>> >
>> > -Steve
>> >
>

Stephany Young wrote:
> > arrayOfLines << new string( "another line" ) ; // adds to the end
> > of the array
> > databaseTable << row ; // adds a row to the database table
> >
> > the general rule being:
> > << adds to something
> > = replaces the contents of something with something else.
>
> And what language might that be defined in?

a great language. one that also allows the programmer to define the
types that a class can be implicitly converted to. that is a feature
C# could benefit from. I dont like casting.

>
> > I have not used bit shifting for years. If you are looking to multiply
>
> Just because you personally have not used a powerful element of the language
> for years, don't assume that other people don't use it regularly.

what do they use it for? I think it makes a poor bit shift because it
ties you too close to the byte size of what is being operated on and
the unit of measure is implied as bits. why not a syntax that allows
you to shift by bits, bytes, characters?
wordValue = wordValue ShiftLeft 2 Bytes ;

-Steve



>
>
> "Steve Richter" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
> >
> > Stephany Young wrote:
> >> Maybe you would like to expand on the 'piping and 'adding' bits.
> >
> > arrayOfLines << new string( "another line" ) ; // adds to the end
> > of the array
> > databaseTable << row ; // adds a row to the database table
> >
> > the general rule being:
> > << adds to something
> > = replaces the contents of something with something else.
> >
> >> Also, what makes you think that bit-shifting is seldom used?
> >
> > I have not used bit shifting for years. If you are looking to multiply
> > or divide, better to use those operators. ( and the optimized compilers
> > of today likely bit shift when we multiply by a constant that is a
> > power of 2. )
> >
> > -Steve
> >
> >
> >
> >
> >>
> >>
> >> "Steve Richter" <(E-Mail Removed)> wrote in message
> >> news:(E-Mail Removed)...
> >> >
> >> > Ben wrote:
> >> >> Hi,
> >> >>
> >> >> I'm trying to figure out the purpose of these operators.
> >> >> Now, I know what they do. They shift bits either left or right.
> >> >> But I don't know why would anybody want to do that. I've never seen
> >> >> anyone using it in his/her code.
> >> >> Any ideas?
> >> >
> >> > it is a tragic mistake that an operator that is tailor made for piping
> >> > and adding to lists, is reserved instead for such a trivial, seldom
> >> > used operation. If you want to shift bits, better to have a new literal
> >> > operator:
> >> > bunchOfBits shiftleft 2 ;
> >> >
> >> > -Steve
> >> >
> >

Hi Steve,

that would be using an operator to change one of it's operands. I think this
is not an OOP way to do it. It surely is not a C#-like way to do. (Though it
would be possible.)
One should use an Add-method instead of that (like in StringBuilder) or the
+ operator like in string, if the type has value semantic.

I suppose the inventors of C# felt this use of the << and >> operators an
abuse of them, so they intentionally forbade it.


"Steve Richter" <(E-Mail Removed)> schrieb im Newsbeitrag
news:(E-Mail Removed)...
>
> Stephany Young wrote:
>> Maybe you would like to expand on the 'piping and 'adding' bits.
>
> arrayOfLines << new string( "another line" ) ; // adds to the end
> of the array
> databaseTable << row ; // adds a row to the database table
>
> the general rule being:
> << adds to something
> = replaces the contents of something with something else.
>
>> Also, what makes you think that bit-shifting is seldom used?
>
> I have not used bit shifting for years. If you are looking to multiply
> or divide, better to use those operators. ( and the optimized compilers
> of today likely bit shift when we multiply by a constant that is a
> power of 2. )
>
> -Steve
>
>
>
>
>>
>>
>> "Steve Richter" <(E-Mail Removed)> wrote in message
>> news:(E-Mail Removed)...
>> >
>> > Ben wrote:
>> >> Hi,
>> >>
>> >> I'm trying to figure out the purpose of these operators.
>> >> Now, I know what they do. They shift bits either left or right.
>> >> But I don't know why would anybody want to do that. I've never seen
>> >> anyone using it in his/her code.
>> >> Any ideas?
>> >
>> > it is a tragic mistake that an operator that is tailor made for piping
>> > and adding to lists, is reserved instead for such a trivial, seldom
>> > used operation. If you want to shift bits, better to have a new literal
>> > operator:
>> > bunchOfBits shiftleft 2 ;
>> >
>> > -Steve
>> >
>

Steve Richter wrote:
> > And what language might that be defined in?
>
> a great language. one that also allows the programmer to define the
> types that a class can be implicitly converted to. that is a feature
> C# could benefit from. I dont like casting.

So you find << to be more obvious than list.Add(...) and you don't like
telling readers of your code when a conversion is taking place. I'm
beginning to spot a pattern here...

By the way, you *can* do implicit conversions in C#. There are some
restrictions, and personally I don't like them because they tend to
reduce readability, but they're available.

Jon