Learning Java

[ultranet 0]

Hey, I'm new and I want to leanr Java, Who can Help me?

[xpress 0]

Hey, I'm new and I want to leanr Java, Who can Help me?

Well, Many people are here to help you. But first let us know what you want. A small suggestion,
posting requests like these in other people's threads may not be good for you...I think.

OK. I will help you. What information do you want? Do you have any doubts? or you want
information like where to start etc..? Feel free to ask anything. But be clear....

[one_nikhil 0]

Hello xpress,Please help me. I am learning java and getting this error in this simple program :-class test { public static void main(String[] args) { byte b = 5; b = b * 2; System.out.println("Answer is "+b+"."); }}Please give me the correct code for this. Thank you in advance.

Edited October 11, 2008 by one_nikhil (see edit history)

[xpress 0]

byte b = 5;

b = b * 2;

System.out.println("Answer is "+b+".");

}

The correct program is,

 

class test {

 

public static void main(String[] args){

 

byte b=5;

b=(byte)(b*2);

 

System.out.println("Answer is "+b+".");

}

}

 

Why did we add byte at b=b*2 ?

Because, java doesn't allow direct arithmetic operations with byte and short(to save from potential loss of precision). Java automatically promotes byte into int here. That is, the result of b*2 will be treated as int rather than byte by java compiler. So we are converting it back to byte by using that keyword before the expression.

 

A small suggestion. Use upper case for first letter in class name(use class Test instead of class test). It is a common convention in java.

Edited October 11, 2008 by xpress (see edit history)

[snowisawsome 0]

I recommend Java For Dummies if you would like to learn Java, it is an excellent reasource. I taught myself Java using that book inconjunction with Java 2 For Dummies, you can also find tutorials online at http://www.oracle.com/technetwork/java/index.html but I find them more confuzing as a first time learning tool.