Different lengths, characters are represented by a number in the computer, that is to say, one character corresponds to a number, so char and int can be converted to each other. The length of int is related to the computer, and different computers may be different, ranging from 32 bits to 64 bits. I haven't tested the single chip microcomputer, because the C language is portable, so the single chip microcomputer and other platforms should be the same and can be converted to each other.