Details of the original code inverse code and complement code storage and size

Details of the original code, inverse code and complement code storage and size

The original code:

If the machine word length is N bit, then the source code of 1 number is N bit 2 base number, the highest bit
It's the sign bit, 1 for a negative number, 0 for a positive number.

Radix-minus-one complement:

The negative of a positive number is the same as the original, the negative of a negative number is the same as the sign bit.

Complement:

The complement of a positive number is the same as its source code; The complement of a negative number is to add 1 to the last bit of its inverse.
(all Numbers in a computer are stored in the form of complement)
The form of the complement is used for adding and subtracting positive and negative 2 bases

char is 1 byte, 8 bit bits, how is it stored in memory

　　　　106 Into the system 2 The actual value of the base (complement) code  
char a = 127; 　 //7f 　0111 1111 　　　　　　　　　　　　　 　 127 
char b = 128; 　//80 　 1000 0000 　0111 1111 　 1000 0000　 -128 
char c = -128;　 //80 　 1000 0000 　 0111 1111　 1000 0000　 -128 
char d = -1; 　　//ff 　 1111 1111 　 1111 1110　 1000 0001 　　-1

-128 and you might have a question, 1000 0000 is a negative number, so if you go back to the complement and the inverse of the original code, you subtract 1 to 0111, 1111, and if you go back to 1000 0000, you get 128, because it's a negative number, you get -128.

So signed char has a maximum of 127 and a minimum of -128.

unsigned is unsigned, meaning there is no sign bit.

　unsigned char e = 256; 　//00  　0000 0000  　 0
   unsigned char f = -1; 　 //ff  　 1111 1111 　 255
   unsigned char g = 255;  //ff 　1111 1111  　 255

Since there is no sign bit, the original reverse complement code is all 1, why is the value of -1 255, the original code of -1 0000 0001 (no sign bit), the inverse code 1111 1110, the complement code

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