Deepakk Verma

I made this code as a practice exercise......this program should be controlled with simply four
cursor control keys and each key must be assigned a method.....i.e., by pressing a particular
key some operation must be performed....what this program do is it should just reflects the changes in the distance traveled and speed of cycle by accelerating and decelerating the cycle and it should also change direction of the cycle(of course imaginary one since i haven't reached to the topics using graphics) .........as stated below

right cursor key(-->) : turnLeft().....and should change the direction as per the code
left cursor key(<--) : turnRight()....and should change the direction as per the code
up cursor key(<) : paddleMoving(int i)....here 'i' states for number of paddle rounds user
wants to apply which would be asked in the starting of the program
down cusor key : applyBrakes()......which eventually stops the cycle.

but the problem is that i dont know how to use Scanner for cursor keys...therefore i have left the class containing main() method.....Please help

public class Cycle { static int distance =0; static int speed = 0; private static int EAST = 0; private static int SOUTH = 1; private static int WEST = 2; private static int NORTH = 3; static int direction; void setDirection(int x) { if(x==EAST | x==SOUTH | x==WEST| x==NORTH) direction = x; else return; } int getDirection() { return direction; } void applyBrakes() { speed = 0; System.out.println("Cycle stoped"); } void paddleMoving(int j) { int k=0; for(int i=0; i<j ;i++) { speed += 5; k = speed; } System.out.println("You are driving at "+k+"Km/Hr"); } void moveHandleLeft() { if (getDirection()==NORTH) { setDirection(WEST); } if(getDirection()==WEST) { setDirection(SOUTH); } if(getDirection()==SOUTH) { setDirection(EAST); } if(getDirection()==EAST) { setDirection(NORTH); } } void moveHandleRight() { if (getDirection()==NORTH) { setDirection(EAST); } if(getDirection()==EAST) { setDirection(SOUTH); } if(getDirection()==SOUTH) { setDirection(WEST); } if(getDirection()==WEST) { setDirection(NORTH); } } }>

OOPS.....i should have taken care of that ............Thanks Maneesh

I am having error in the program can anybody help please
public class StringDemo2 { public static void main(String args[]) { String strob[] = new String[4]; String alpha = "abcdefgh"; for(int i=0; i<4;i++) { strob[i] = alpha.charAt(i); } } }

Error is in 7th line as:
Type mismatch: cannot convert from char to String

Thank you guys

Can we apply right shift(>>), and left shift (<<) operator to float and double type values?..
if not why?
Please explain...

Is new used only to allocate memory for an object.......i mean if i do something like
class Test { public static void main(String args[]) { int i; int []f = new int[100]; for(i=0;i<101;i++) { f[i] = i; System.out.print(" " + f[i]); } } }
Will this create an array of integer type or there is some predefined class named as int whose
object is it creating.....
please explain

if somebody else also has some useful information regarding new then please share

It took me a little while to grasp the idea but i thing i am able to digest the concept now
Thank you very much Mr Pankaj for your valucble efforts to explain this all....
Thank you again
Deepak Verma

4. Using RefVariable you can access static variable of superclass.

Can we also access the private instance variables of the superclass by RefVariable?

i know that and i also apologized for it
actually i gave the 128 value by mistake in that post so please dont be annoyed

i have a shadow of doubt about the concept of object declaration
i would illustrate my doubt with an example

class superclass { int superIntsnceVariable = 1; void superClassMethod() { System.out.print("this is superclass method."); } } class subclass extends superclass { int subInstnceVariable = 2; void subClassMethod() { System.out.println("this is subclass method."); } } class Test { superclass RefVariable = new subclass(); }


The statement

superclass RefVariable = new subclass();

it will create memory space for an object of "subclass" class and would appoint a variable of type superclass named as RefVariable with the reference of the object created .....
Now my questions rare :
what this RefVariable actually contains?
what are its capability?
Is it carrying a pointer to the superclass object?
Or is it carrying some sort of address to a memory location?
I am really confused with this....please help

soory for the misteake......it was 127+127
and was getting -2.....
please try once more

if i change this code to

class BasicMath { public static void main(String[] args) { Adder adder = new Adder(); byte y= adder.addAndReturn((byte)127,(byte)127); // arguments casted and passing to the function System.out.println("Added value is"+y); } } class Adder { byte addAndReturn(byte firstNum, byte secondNum){ byte t = (byte)(firstNum + secondNum);// -------------> this statement return (t); } }

then why is it showing me result as -2
point to be noted is: byte range is -128 to 127
so what it should do on line 14 is add the two number
127+127 i.e, 254
there will be no changes in the value since 127 is in the range of byte
now it will do type casting and will display the reduced modulo(the remainder of an integer division by the) byte's range(which i guess is 127)

and the result should be

254/127=2 with remainder =0
thus 0 should be the result but it is showing me -2 ?........Please explain

allright..that is a lot of valuable information you gave me....
thanks very much to you all especially to Rahul, Campbell and D. Ogranos
Deepak Verma

if i write this code
public class Box { int a,b; Box(int i,int j) { a = i; b = j; } } public class BoxDemo { public static void main(String args[]) { Box mybox = new Box(15,20); System.out.println("mybox"+mybox); } }

it is giving me result as

myboxBox@19821f


can you tell me why?
(i know this code is of no use but i was curious to know why is it generating this output)

please explain....

ok....now i got it
Thanks Mr.Rahul