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Feb 16th, 2007
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Range of int

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Unsigned char is 1 byte long..
it's range is from -128 to 127
Most significant bit is sign bit to indicate whether the char has positive or negative value and the rest 7 bits are meant for storing the actual value of char... so the max +ve value of char can be 127 as expected but in the -ve side how can it be -128 ???
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Re: Range of int

0xFF is the largest value that can be stored in one byte, for signed integers that is 0xFF/2, which is 127.5 (use a calculator if you must). Since you can put 0.5 in a byte, one side is 127 and the other is 128 so that 127+128 = 255 (0xFF).

limits.h contains the upper and lower limits of all numeric data types supported by your compiler.
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Re: Range of int

The reason that it's -128 and 127 breaks down like this: You have 8 bits. One of them is for sign. That leaves 7 bits for the value, or 128 values. One side is 0 to 127. Since you already have 0, the other half is -1 to -128.
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Re: Range of int

Thanks for ur reply but there are actually 256 values 127 +128+one zero is also there.....and one more thing I can't understand 7 bits (1111111) can contain maximum of 127 so then how value 0f -128 is stored..
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Re: Range of int

Read up on how Two's Complement works and hopefully you'll see. It comes down to 0 being counted as a positive number, and 1-127+0 is a total of 128 numbers; there's an equal number of negatives, but since it doesn't include 0, you get 1-128.
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Re: Range of int

Click to Expand / Collapse  Quote originally posted by himanjim ...
Unsigned char is 1 byte long..
it's range is from -128 to 127
At least; it can be larger.

Click to Expand / Collapse  Quote originally posted by himanjim ...
Most significant bit is sign bit to indicate whether the char has positive or negative value and the rest 7 bits are meant for storing the actual value of char... so the max +ve value of char can be 127 as expected but in the -ve side how can it be -128 ???
Two's complement?
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Re: Range of int

Click to Expand / Collapse  Quote originally posted by himanjim ...
Unsigned char is 1 byte long..
it's range is from -128 to 127
Just noticed... an unsigned char has values 0 to 255, and a signed char is -128 to 127.

That said, I seem to recall in some discussions that a char is strictly defined as a single byte (8 bits) by the standard but I'm not sure where to double check that...
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Re: Range of int

Click to Expand / Collapse  Quote originally posted by Infarction ...
Just noticed... an unsigned char has values 0 to 255, and a signed char is -128 to 127.

That said, I seem to recall in some discussions that a char is strictly defined as a single byte (8 bits) by the standard but I'm not sure where to double check that...
In C (and derivatives) a byte is not defined as 8 bits.
Last edited by Dave Sinkula; Feb 17th, 2007 at 4:30 am.
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Re: Range of int

Byte is not defined as 8 bits then what is it defined as?
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Re: Range of int

>Byte is not defined as 8 bits then what is it defined as?
It's defined as whatever the implementation wants. The standard only specifies that sizeof ( char ) be 1, and at least 8 bits. That happens to be the most common definition of a byte, but systems other than your PC also support C and don't have the same definition.
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