Why the output is like this

Question

https://code.sololearn.com/cZ7Dnn3ilWOO/?ref=app

Answer 1

A signed value will count its last digit (in binary) as negative value. In this example, a char has a size of 1 byte, 128 in binary is 1000000, therefore the last digit is actually -128. A char is also signed by default

Answer 2

I think range of char is -128 to 127 and +128 is not n the range of char
Therefore it is in -ve