Java: convert number into ASCII equivalent, how does it work?

Question

Here is the code, it works, it converts 66 into the ASCII equivalent of B.

int ascii = 66;
char character = (char) ascii;

What I don't understand is, how does it work? If this was an exam paper, what would you write?

The question would be, describe how the program converts it into a "B". Is char a function?

`char` is a type and there is nothing to do to display 66 as 'B'. In fact to display `66` requires conversion to two characters 54 and 54 which print as `6` and `6`. — Peter Lawrey, Jun 02 '13 at 08:53

Tejas Patil · Answer 1 · 2013-06-02T07:58:08.217

0

"char" => "int" is called Widening Primitive Conversion and "int => char" is called Narrowing Primitive Conversion

In Java, a char is just a 16-bit integer. When casting ints (which are 32-bit integers) to chars, you are keeping the 16 least significant bits of the int, and discarding the upper 16 bits. This is called a narrowing conversion. Java characters are represented as members of the Unicode character set. The Unicode value of 'B' is 66.

int ascii = 66;

The integer value 66 is assigned to ascii.

char character = (char) ascii;

character stores the first 16 bits of the integer ascii. Storing 66 doesnt exceed 16 bits so the char variable gets it right

edited Jun 02 '13 at 07:58

answered Jun 02 '13 at 07:21

Tejas Patil

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@BrianRoach i know :( i was in a haste to save the comment. I have completed it now – Tejas Patil Jun 02 '13 at 07:27
Thanks, so would converting a char (B) into 66 be widening conversion? – user2421111 Jun 02 '13 at 07:29
what did u mean by 66 ? int or a char ? see my edit above – Tejas Patil Jun 02 '13 at 07:50
And can you tell me what String qwe = ""; means? I know it gives qwe the value "", but assuming this was an exam question, what would the answer be? That qwe was initialised with the value ""? Would that be good enough? – user2421111 Jun 02 '13 at 21:15

Java: convert number into ASCII equivalent, how does it work?

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