Query on integer range in a Programming Language

Question

All,

This might be a very silly question, but in a Programming lang X where the int range is -127 to +128, does this value refer to the actual value -127 and +128 ?

Answer 1

What do you mean?

It will typically mean -127 to 128 inclusive, so both -127 and 128 are themselves valid values.

Answer 2

Normally, the ranges of the values indicates how much memory they use, and they are normally designed to ocuppy full bytes. In your case (-127 to 128), this type will occupy 1 byte, which can have 256 different values.

So, you have 127 negative values, 128 positive values, and the 0 value. 127 + 128 + 1 = 256.

So, the values -127 and 128 are included in the range.

Answer 3

It refers to an 8-bit signed integer, where the high bit is used to determine whether it's negative or not:

01111111 = 127
00000001 = 1
00000000 = 0
11111111 = -1
11111110 = -2
10000001 = -127
10000000 = -128 or +128 or even -0, depending on the language

See: http://en.wikipedia.org/wiki/Two%27s_complement