char data type.....

[albertlee]

In Java,

 

char is an unsigned data type

 

 

Does any one know what does "unsigned" mean in that sense???

 

thx

 

Albert

[Dave]

It means that the number is always going to be positive. There's no bit to signify whether the number is positive or negative. A char is just a 1-byte data type (holds integers from 0-255), and the associated integers are matched up with the ASCII table.

[albertlee]

Oh, so, do you mean that the left most bit of a byte is always 0 in char???

 

Albert

[Cadmus]

A char is just a 1-byte data type (holds integers from 0-255), and the associated integers are matched up with the ASCII table.

I think that you made a typo. In Java, the char data type is a 2 byte unsigned integer. The purpose of the 2 byte type was that Java was designed early on to support unicode.

[Dave]

I missed the "in Java" bit, sorry. In most of the programming languages I know, a char is only 1 byte, but fair enough

[albertlee]

Any one can refer to my previous message??

 

thx

 

Albert

[Cadmus]

Oh' date=' so, do you mean that the left most bit of a byte is always 0 in char???

[/quote']

This is not correct. In a signed byte, there is one sign bit and 7 data bits. The maximum number of distinctions is 128 (2^7), which can be postive or negative, depending on the sign (range: -128 - +127). In the high order byte of the char type, there is no sign bit. Therefore, all 8 bits pertain to the value, the maximum number of distinctions of which is 256 (2^8), with the range 0 - 255.