Reputation: 1317

What is the purpose of Signed Char

what is the purpose of signed char if both char and signed char ranges from -127 - 127? what is the place where we use signed char instead of just char?

Upvotes: 5

Answers (4)

shishir choudhary

Reputation: 31

See lamia,

First I want to prepare background for your question.
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char data type is of two types:

unsigned char;

signed char;

(i.e. INTEGRAL DATATYPES)

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Exaplained as per different books as:
char 1byte –128 to 127 (i.e. by default signed char)

signed char 1byte –128 to 127

unsigned char 1byte 0 to 255

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one more thing 1byte=8 bits.(zero to 7th bit)

As processor flag register reserves 7th bit for representing sign(i.e. 1=+ve & 0=-ve)

-37 will be represented as 1101 1011 (the most significant bit is 1),

+37 will be represented as 0010 0101 (the most significant bit is 0).

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similarly for char last bit is by default taken as signed

This is why?

Because char also depends on ASCII codes of perticular charectors(Eg.A=65).

In any case we are using char and using 7 bits only.

In this case to increase memory range for char/int by 1 bit we use unsigned char or unsigned int;

Thanks for the question.

Upvotes: 2

James Kanze

Reputation: 154047

It is implementation defined whether plain char uses the same representation as signed char or unsigned char. signed char was introduced because plain char was underspecified. There's also the message you send to your readers:

plain char: character data
signed char: small itegers
unsigned char: raw memory

(unsigned char may also be used if you're doing a lot of bitwise operations. In practice, that tends to overlap with the raw memory use.)

Upvotes: 7