tell me easiest way

[Dhanesh Kumar]

Hi friends
see the following code;

byte b=127 // ok
s.o.p(b)// Ans is 127;

byte b=128 // Compile time error;
So we need to type cast by explicitly

byte b=(byte)128 /// ok
s.o.p(b)// ans is –128

if suppose I will write

byte b=(byte) 540 // ok
s.o.p(b)//Ans is 28

I know the how the 28 has to come. But my way is very difficult to find .
So please any one tell me to find ans above or follows.

byte b=(byte)989;
s.o.p(b) // what is ans and how to find the ans by easiest way

[Timmy Marks]

Convert to binary and take the 8 least significant bits as signed:

989 decimal = 1111011101 binary. the least significant 8 bits are
11011101 which is -35 decimal.


Upon experimentation, and with absolutely no proof whatsoever, in the cases here, you can continually subtract 256 until you are in the range of -128 to 127. That may be easier if it is correct.
[ May 10, 2005: Message edited by: Timmy Marks ]

[deepu Bhalotia]

I myself have found the easiest way to remember this. Check it if ok you also can use the same..


byte a=127;
System.out.println(a);
127 will be printed on the Console.

byte a=(byte)128;
System.out.println(a);
-128 will be printed on the Console. since Byte is of size 256 (2^8).
you need to do the following calculation.

128-256=-128.


byte a=(byte)540;
System.out.println(a);
28 will be printed on the Console. For the number greater than 256. First take the modulo of that number Like- 540%256.

Calculation-
540%256=28. Since this number is less than 127. There is no need to deduct it from 256.

byte b=(byte)989;
s.o.p(b) // what is ans and how to find the ans by easiest way
Take the modulo of this number.
989%256=221
Now
221-256=-35 will be printed on the Console..

Check it and rectify me if i am wrong....

Deepak

[ May 10, 2005: Message edited by: deepu Bhalotia ]
[ May 10, 2005: Message edited by: deepu Bhalotia ]

[Ashok Kumar]

I found a round about way for this.If anybody has an easier way please reply

for
byte b=(byte)256;
sop(b);
we get b=0;

So if x is the number its equivalent byte value is got by the formula

(x%256)(for x>127)

[Dhanesh Kumar]

hi

I continual subtract 128 . but it sometime going to wrong output. That is I assure positive number means it will give negative number…

[Timmy Marks]

Are you looking for the easiest way in your head/on paper or the easiest way for a computer? I would assert that the computer can do it more easily with the %256 method, but that most people can do it for most smaller numbers with the -256 method. For extremely large numbers, I would recommend converting the lowest 8 bits to binary as the quickest method.

[Dhanesh Kumar]

Yes u r exactly correct
Thanks