Scratch

Mokat wrote:

I don't know when I would use them, but I can see where it would be helpful for some people. Support 

Ever heard about huffman coding ??

with bitwise operators we can logically compress our datacontaining projects or can even decode real world files in scratch :-)

scimonster wrote:

I'm not even sure what these are; care to explain? :P

Well, there are several

I don't know if bit shifts count, but I'll say 'em anyway.
Generally done with >> and << commands in other programming languages, these shift a number over. So say if you have 000110100101110, if you do << 2 then you'll get 011010010111000. >> goes the other way and truncates.

NOT does logical negation, so NOT 100101 is 011010. It's sometimes referred to with ~.

AND takes two numbers. If both have a one in the same place, then the result will have it. So 1101 AND 0111 will give you 0101. It's sometimes done with &, as opposed to the logical AND (&&).

OR takes two numbers. If either number has a one in a place, the result has a one in that place.  01101001 OR 10011000 will give you 11111001. Often represented by |, as opposed to the logical OR (||).

XOR, or exclusive or, takes two numbers. If only one number has a one in a place, then that place in a result will have a one. 01101 XOR 11111 equals 10010. This is commonly used for inverting an image and is often represented by ^ in programming.

Here's more explanation.

Last edited by veggieman001 (2012-04-29 11:24:55)

veggieman001 wrote:

scimonster wrote:

I'm not even sure what these are; care to explain? 

Well, there are several

I don't know if bit shifts count, but I'll say 'em anyway.
Generally done with > > and < < commands in other programming languages, these shift a number over. So say if you have 000110100101110, if you do << 2 then you'll get 011010010111000. > > goes the other way and truncates.

NOT does logical negation, so NOT 100101 is 011010. It's sometimes referred to with ~.

AND takes two numbers. If both have a one in the same place, then the result will have it. So 1101 AND 0111 will give you 0101. It's sometimes done with &, as opposed to the logical AND (&&).

OR takes two numbers. If either number has a one in a place, the result has a one in that place.  01101001 OR 10011000 will give you 11111001. Often represented by |, as opposed to the logical OR (||).

XOR, or exclusive or, takes two numbers. If only one number has a one in a place, then that place in a result will have a one. 01101 XOR 11111 equals 10010. This is commonly used for inverting an image and is often represented by ^ in programming.

Here's more explanation.

Lovely post :-) +1

These are not generally used but when used these can do awesomness say for instance i will consider an mp3Frame header :-) its just 4 bytes but these 32 bits are soo nicely written that each bit has its own meaning :-) and when u wanna go to the level of handling bits , bitwise operators are the only solution you have :-)

here is a small example of there use in javascript

/* Snippet to read mp3 frame header * /
                                        var ver = ( buffer.head[1] & 0x18)>>>3;
                    var layer = ( buffer.head[1]& 0x6 )>>>1;
                    var crc = ( buffer.head[1]&0x1 );
                    var bitrate = ( buffer.head[2] & 0xF0 )>>>4 ;
                    var samplerate = ( buffer.head[2] & 0xC)>>> 2;
                    var padding = ( buffer.head[2] & 0x2)>>>1;
                    var priv = ( buffer.head[2]& 0x1 );
                    var channel = ( buffer.head[3] & 0xC0 )>>>6; 
                    var jsExt =  ( buffer.head[3]& 0x30)>>> 4; /* joing stereo ext */
                    var cpyrite = ( buffer.head[3]& 0x9)>>> 3;
                    var orig = ( buffer.head[3] & 0x4 )>>>2;
                    var Emph = ( buffer.head[3] & 0x3 );

Now each element in buffer has like 1 byte of data but you can see how much data are we extracting from just 3 bytes of data :-) makes sense ?? It can open a whole new paths for programmers using scratch ,

moreover    they are extremely fast 

Last edited by fanofcena (2012-04-30 03:50:39)

trinary wrote:

It would be nice, but Scratch...is for learning to program.
It's primarily for beginners.
It may be confusing for them.

However, I still support.

Well scratch has a lot of things in the arithimetics secion which can confuse :-) , and by the way language without bitwise operators cannot be called a real programming language now can it ?