'\r' 回车，回到当前行的行首，而不会换到下一行，如果接着输出的话，本行以前的内容会被逐一覆盖； '\n' 换行，换到当前位置的下一行，而不会回到行首；('\ r' carriage return, back to the current line of the first line, and not to the next line, if the next output, then the contents of the Bank will be covered one by one;