源程序的输入和扫描 编制一个源程序的输入过程，从键盘、文件或文本框输入若干行语句，依次存入输入缓冲区（字符型数据）；并编制一个扫描子程序，该子程序中每次调用能依次从存放源程序的输入缓冲区中读出一个有效字符。-The preparation of a source program input process, the keyboard, file or text box to enter a number of line statements, which are stored in the i