You can compile the input process of a source program, input several lines of statements from the keyboard, file or text box, and store them in the input buffer (character data) in sequence; then compile a preprocessing subroutine to remove the carriage returns and carriage return characters in the input string. Editing text such as line breaks and tabs; merge multiple blank characters into one; remove comments; and record the line number. It is assumed that the SAMPLE language is written in free format, and whitespace is used as a separator. Annotations can be used, marked with /*...*/ or {...}, but annotations cannot be inserted inside words. Annotations must end in one line. If a line ends , if the end mark after the comment is not encountered, the comment is automatically considered to have ended.