The value of integer a after bitwise negation (~) is - (a+1)

【 Understanding bitwise negation （~） The original code you need to know before 、 Inverse code 、 The complement rule 】
Data is stored in memory in the form of the complement of signed binary numbers . In the binary representation of signed integers , The highest bit is the sign bit （ The positive integer is 0, Negative integer is 1）, This is also the origin of signed integer names .
● The original code of a positive number 、 Inverse code 、 The complement is the same .
● The inverse of a negative number is equal to the sign bit of the original code , The rest of you take the opposite ; The complement of a negative number is the inverse plus 1.

【 Examples of bitwise negation operations are as follows 】

 negative ：-1
 Original code ：1000 0001
 Inverse code ：1111 1110 （ The sign bits remain the same ）
 Complement code ：1111 1111 （ The sign bits remain the same ）
 
 According to the not ：0000 0000 （ The sign bit is also reversed ）
 Because the sign bit is 0, Is a positive number . Therefore, complement is equal to the value after bitwise inversion  0000 0000, Its decimal system is 0. That is to say -(-1+1)=0
 
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 negative ：-10
 Original code ：1000 1010
 Inverse code ：1111 0101 （ The sign bits remain the same ）
 Complement code ：1111 0110 （ The sign bits remain the same ）
 
 According to the not ：0000 1001 （ The sign bit is also reversed ）
 Because the sign bit is 0, Is a positive number . Therefore, complement is equal to the value after bitwise inversion  1111 0110, Its decimal system is 9. That is to say -(-10+1)=9
 
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 Positive numbers ：1
 Original code ：0000 0001
 Inverse code ：0000 0001 （ The sign bits remain the same ）
 Complement code ：0000 0001 （ The sign bits remain the same ）
 
 According to the not ：1111 1110 （ The sign bit is also reversed ）
 Because the sign bit is 1, It's a negative number . There are ：
 Original code ：1111 1110
 Inverse code ：1000 0001 （ The sign bits remain the same ）
 Complement code ：1000 0010 （ The sign bits remain the same ）
 
 Therefore, the decimal system corresponding to the complement is -2. That is to say -(1+1)=-2
 
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 Positive numbers ：10
 Original code ：0000 1010
 Inverse code ：0000 1010 （ The sign bits remain the same ）
 Complement code ：0000 1010 （ The sign bits remain the same ）
 
 According to the not ：1111 0101 （ The sign bit is also reversed ）
 Because the sign bit is 1, It's a negative number . There are ：
 Original code ：1111 0101
 Inverse code ：1000 1010 （ The sign bits remain the same ）
 Complement code ：1000 1011 （ The sign bits remain the same ）
 
 Therefore, the decimal system corresponding to the complement is -11. That is to say -(10+1)=-11

0 Not a positive number , It's not a negative number . But the operation rule of bitwise negation is the same as above .

 Integers ：0
 Original code ：0000 0000
 Inverse code ：0000 0000 （ The sign bits remain the same ）
 Complement code ：0000 0000 （ The sign bits remain the same ）
 
 According to the not ：1111 1111 （ The sign bit is also reversed ）
 Because the sign bit is 1, It's a negative number . There are ：
 Original code ：1111 1111
 Inverse code ：1000 0000 （ The sign bits remain the same ）
 Complement code ：1000 0001 （ The sign bits remain the same ）
 
 Therefore, the decimal system corresponding to the complement is -1. That is to say -(0+1)=-1

Sum up ：
Integers a According to the not （~） The value after is -(a+1)

【 reference 】
https://blog.csdn.net/hnjzsyjyj/article/details/125857019
https://blog.csdn.net/hnjzsyjyj/article/details/119720322
https://blog.csdn.net/hnjzsyjyj/article/details/120794381
https://blog.csdn.net/qq_34681580/article/details/115248595