I can't imagine suffering from that. Understanding twos complement representation is an essential programming skill. And a byte value of 128? What is that in hex?
For most practical purposes outside of low-level stuff all that really matters about two's complement is Don't Get Near 2^(width-1) Or Bad™ Things Happen. Including +128 would even have the benefit of 1<<7 staying positive.
The work needed to calculate the overflow flag (done in every add/sub operation in most ISAs) is also way more complicated when the high bit does not represent sign.
The field of programming has become so broad that I would argue the opposite. The vast majority of developers will never need to think about let alone understand twos complement as a numerical representation.
It is completely irrelevant for the vast majority of programming.
While "twos complement" turns the MSB unsigned value to a negative instead of a positive. For example, 4-bit twos complement: 1000 represents -8 (in unsigned 4-bit, this supposed to be +8), 0100 represents 4, 0010 represents 2, 0001 represents 1. Some more numbers: 7 (0111), -7 (1001), 1 (0001), -1 (1111).
Intuitively, "ones complement" MSB represents a multiplication by (-1). While "twos complement" MSB adds (-N), with N = 2^(bit length - 1), in case of 4-bit twos complement it's (-2^3) or (-8). Both representation leave non-MSB bits work exactly like unsigned integer.
I find the best way to understand why 2s complement is so desirable is to write down the entire number line for e.g. 3-bit integers.
Using 1s complement, the negative numbers are backwards. 2s complement fixes this, so that arithmetic works and you can do addition and subtraction without any extra steps.
(Remember that negative numbers are less than positive numbers, so the correct way to count them is:
-8 -7 -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6 +7
Where -1 is the largest possible negative number)
> And a byte value of 128? What is that in hex?
0x80
Which is of course has the sign bit set.
The comments here are educational ... I hadn't realized that the field of programming had become this degraded.
1. Unrepresentable in S8
2. Representable in U8 as shown in my above comment.
3. Representable in S16 as 0x0080 but then the sign bit is not set.
THAT comment is condescending--talk about ideas, not people. I condescended to no one ... my issue is the state of computer science education.
> On the contrary, there is no sign bit. You asked for 128
I didn't ask for anything. The subject here was the value range of the i8 type.
To quote you: "What is that in hex?"