converting hexa decimal into int

[sanla palati]

Hi ,


How to convert the hexadecimal value 0xbeef into int.

[Sekhar Kadiyala]

Are you looking for manual integer conversion or methods of wrapper classes?

[Kelvin Chenhao Lim]

Integer.decode() should do the trick, though I believe this is outside the scope of the SCJP exam.

[Burkhard Hassel]

Howdy!

0xbeef is already an int, an int literal to be precise. Only it is not written in decimals but in hexadecimals.


int i = 0xbeef;
System.out.println(i);

prints out the value in decimals.


Yours,
Bu.

[sanla palati]

Thanks for your replys guys.But Burkhard, how can i know that 0xbeef is an interger. I am confused.

[Jesper de Jong]

Hexadecimal is not a separate data type. It is just a way to write numbers - in the base-16 numeric system instead of base-10 (decimal). When an integer literal in Java code starts with "0x", then it's in hexadecimal.

In addition to hexadecimal, you can write numbers in octal (the base-8 number system). A number is interpreted as octal if it starts with "0".

[Burkhard Hassel]

Sanla asked

how can i know that 0xbeef is an interger

You're right, at a first glance 0xbeef looks more like something to eat than like an integer for many people.
Similarly, 0xCAFE looks more like something to drink than like the number 51966.

But you have to know about the other two ways of writing an integer.
Perhaps try this as a primer:

class Main {
public static void main(String[] args) {
int i = 1; // to begin with  :wink: 
while (i<20) {
System.out.print(i + "\t");
System.out.print(Integer.toBinaryString(i) + "\t");
System.out.print(Integer.toOctalString(i) + "\t");
System.out.println(Integer.toHexString(i) + "\t");
i++;
}
}
}

I'm terribly sorry that this output ends in a thirteen.
But hopefully you are not supersticious.
Ah, no, it doesn't end in a thirteen but in a nineteen!!!
Phew!

Yours,
Bu.