help me to understand codes.

[shana07]

I can't understand this code...I need somebody to help me to understand this code.please.
This is from MutableBigInteger java core class..

What is this mean? >> // Special case one word numbers .....
Am I right by saying numbers between 0 - 9 as an example?
How about the int x & int y, kindly please gimme examples of them...
Thank you very much

while ((lb = t.getLowestSetBit()) >= 0) 
        {
            // steps B3 and B4
            t.rightShift(lb);
            // step B5
            if (tsign > 0) 
                u = t;
            else
                v = t;
 
            // Special case one word numbers   
            if (u.intLen < 2 && v.intLen < 2) 
            {
                int x = u.value[u.offset];  // this part
                int y = v.value[v.offset];    // this part
                x  = binaryGcd(x, y);  
                r.value[0] = x;
                r.intLen = 1;
                r.offset = 0;
                if (k > 0)
                    r.leftShift(k);
                return r;
            }
 
            // step B6
            if ((tsign = u.difference(v)) == 0)
                break;
            t = (tsign >= 0) ? u : v;
        }

[JosAH]

I can't understand this code...I need somebody to help me to understand this code.please.
This is from MutableBigInteger java core class..

What is this mean? >> // Special case one word numbers .....
Am I right by saying numbers between 0 - 9 as an example?
How about the int x & int y, kindly please gimme examples of them...
Thank you very much

while ((lb = t.getLowestSetBit()) >= 0) 
        {
            // steps B3 and B4
            t.rightShift(lb);
            // step B5
            if (tsign > 0) 
                u = t;
            else
                v = t;
 
            // Special case one word numbers   
            if (u.intLen < 2 && v.intLen < 2) 
            {
                int x = u.value[u.offset];  // this part
                int y = v.value[v.offset];    // this part
                x  = binaryGcd(x, y);  
                r.value[0] = x;
                r.intLen = 1;
                r.offset = 0;
                if (k > 0)
                    r.leftShift(k);
                return r;
            }
 
            // step B6
            if ((tsign = u.difference(v)) == 0)
                break;
            t = (tsign >= 0) ? u : v;
        }

That piece of code tries to determine whether or not such a BigInteger would
fit in a single (primitive) int after a bit of shifting; this implies that all the bits set
to '1' are no further apart than 32 positions; if so the values fit in such an int.

kind regards,

Jos

[shana07]

That piece of code tries to determine whether or not such a BigInteger would
fit in a single (primitive) int after a bit of shifting; this implies that all the bits set
to '1' are no further apart than 32 positions; if so the values fit in such an int.

kind regards,

Jos

In short - it's shifting BigInteger bit positions (and values) until become integer..
sort of...?
Thank You

[shana07]

Sorry, one more question from me, what is the magnitude...and how does it look like?
Thank you again...

/**
     * Holds the magnitude of this MutableBigInteger in big endian order.
     * The magnitude may start at an offset into the value array, and it may
     * end before the length of the value array.
     */
    int[] value;

[JosAH]

Here's a question for you: there is no MutableBigInteger class in the core set
of classes in the JSE. Where did you get that class from?

kind regards,

Jos

[shana07]

Here's a question for you: there is no MutableBigInteger class in the core set
of classes in the JSE. Where did you get that class from?

kind regards,

Jos

Yes, there is MutableBigInteger class in the core set.
This is a path to the class in my pc.
C:\Program Files\Java\jdk1.5.0_07\src\java\math

Is there anything wrong in here.....

[JosAH]

Yes, there is MutableBigInteger class in the core set.
This is a path to the class in my pc.
C:\Program Files\Java\jdk1.5.0_07\src\java\math

Is there anything wrong in here.....

Feel free of course to study all sorts of classes but MutableBigInteger isn't
a publicly available class and therefore there are no API documents for it to
be found in the API documentation, not is the API itself publicly available.
It's just a helper class for internal use only.You (nor I) can use it because
it's only available for other classes in the java.math package.

kind regards,

Jos

ps. why did you unzip that sources zip file?

[shana07]

Feel free of course to study all sorts of classes but MutableBigInteger isn't
a publicly available class and therefore there are no API documents for it to
be found in the API documentation, not is the API itself publicly available.
It's just a helper class for internal use only.You (nor I) can use it because
it's only available for other classes in the java.math package.

kind regards,

Jos

ps. why did you unzip that sources zip file?

Thanks for the good explanation...I like the way you describe, really.
Since you mentioned about API documents, How do you do that?
I really have no idea how to check API docs ...because I use netbeans, so usually if I wanna check where is the method's located, I right click and go to declaration.

So from there I found the GCD method is in java.math package, so I did unzip them just because I need to copy and alter them due to my java class assignments....

Kindly please advise me. thanks

[JosAH]

Since you mentioned about API documents, How do you do that?
I really have no idea how to check API docs ...

Have a look at this little thread. The eastiest thing
is to download all the API documentation and bookmark it in your browser for
easy access.

kind regards,

Jos