Code bug correction, char is converted to int high-order symbol extension, resulting in changes in positivity and negativity and values. Int num = (int) (unsigned int) a, which will occur in older com

Code bug correct ,char Convert to int High sign extension , Cause the positive and negative and numerical values to change ,int num = (int)(unsigned int)a, Problems with older compilers

scene ：
char The data type is converted to int when , If you use
char a = 0x9A;
int num = (int)a;
It can be calculated that a Of int The value should be 154, But the actual code is -102, A logical error has occurred .

reason ：
To explain in detail, we need to talk about the expression of negative numbers in computers , Need to add a complement or something , This aspect is not very good for the time being .

resolvent ：
char a = 0x9A;
int num = (int)(unsigned int)a;